Methods and devices for non-invasive root phenotyping

ABSTRACT

The present disclosure provides for an electronic sensor for detecting a root of a plant in soil, the electronic sensor that includes a first conductor plate configured to be disposed in soil, a switch, a power supply, and signal extractor. The switch is electrically coupled to the first conductor plate and is configured to switch between a first mode and a second mode. The power supply is electrically coupled to the switch and is configured to provide an electrical charge to the first conductor plate in the first mode of the switch. The signal extractor is electrically coupled to the switch and is configured to extract a signal response at the first conductor plate in the second mode of the switch. The present disclosure further provides a second conductor plate configured to be disposed in soil adjacent to and substantially parallel to the first conductor plate. The second conductor plate is electrically coupled to ground.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Provisional Application No.62/259,587, entitled “METHODS AND DEVICES FOR NON-INVASIVE ROOTPHENOTYPING,” filed Nov. 24, 2015, which is hereby incorporated byreference in its entirety,

BACKGROUND Field

The present disclosure generally relates to devices for non-invasiveroot phenotyping and more specifically to an electronic system andelectronic devices to detect plant roots, as well as monitor plant roottraits over time.

Description of Related Art

Root system architecture (RSA) describes the spatial arrangement ofroots within the soil that is shaped by genetic and environmentalfactors. The RSA impacts plant fitness, crop performance, grain yield,and can influence a plant's drought tolerance and ability to acquirenutrients. For example, studies have shown that modifying a single gene,DEEPER ROOTING 1 (DRO1), in rice changes the root angle without changingthe overall length of the root. This slight change in root angle directsthe roots downward, which provides the plant with more access togroundwater. As such, the modified rice (e.g., rice with the DRO1 gene)yields 10% less under drought conditions, whereas unmodified rice (e.g.,rice without the DRO1 gene) yields 60% less under the same conditions ascompared to well-watered conditions.

Root traits rarely have been applied to breeding programs due, in part,to the difficulty in measuring and monitoring root growth in opaque andcomplex soils. Current techniques either reduce crop yield or interferewith the plants growing cycle. One technique, for example, uprootsfield-grown plants for a single time-point measurement. Not only is thistechnique destructive, but the uprooting process changes in situ factors(e.g., removes the soil foundation), which can bias the measurements(e.g., root angle measurements without soil).

A less destructive technique provides a viewing window such as arhizotron to observe the roots over time. This technique places atransparent barrier in the path of root growth in order to view theroots that grow adjacent the viewing window of the rhizotron camera.This technique interferes with the plant's natural growing cycle, as itintentionally places an obstruction in the natural path of rootdevelopment.

Real-time monitoring of the RSA during the growing season withoutinterfering with the plant's growing cycle can provide invaluableinformation that can be used to produce healthier plants and yield amore abundant crop. As such, a challenge exists for improved,non-invasive techniques for monitoring root phenotypes, such as growthrate, length, angle, and the like.

BRIEF SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such examples. This summary isnot an extensive overview of all contemplated examples, and it isintended to neither identify key or critical elements of all examplesnor delineate the scope of any or all examples. Its purpose is topresent some concepts of one or more examples in a simplified form as aprelude to the more detailed description that is presented below.

In some examples, the present disclosure provides an electronic sensorfor detecting a root of a plant in soil, the electronic sensorcomprising: a first conductor plate configured to be disposed in soil; aswitch electrically coupled to the first conductor plate, wherein theswitch is configured to switch between a first mode and a second mode; apower supply electrically coupled to the switch, wherein the powersupply is configured to provide an electrical charge to the firstconductor plate in the first mode of the switch; and a signal extractorelectrically coupled to the switch, wherein the signal extractor isconfigured to extract a signal response at the first conductor plate inthe second mode of the switch. In certain examples, the presentdisclosure further provides a second conductor plate configured to bedisposed in soil adjacent to and substantially parallel to the firstconductor plate, wherein the second conductor plate is electricallycoupled to ground.

In some examples, the present disclosure provides an electronic devicefor monitoring growth of a root of a plant in a soil location,comprising: a support structure suitable for arrangement adjacent to thesoil location; and a plurality of electronic sensors affixed to thesupport structure, wherein at least one electronic sensor of theplurality of electronic sensors comprises: a first conductor plateconfigured to be disposed in soil; a switch electrically coupled to thefirst conductor plate, wherein the switch is configured to switchbetween a first mode and a second mode; a power supply electricallycoupled to the switch, wherein the power supply is configured to providean electrical charge to the first conductor plate in the first mode ofthe switch; and a signal extractor electrically coupled to the switch,wherein the signal extractor is configured to extract a signal responseat the first conductor plate in the second mode of the switch. Incertain examples, the present disclosure further provides a secondconductor plate configured to be disposed in soil adjacent to andsubstantially parallel to the first conductor plate, wherein the secondconductor plate is electrically coupled to ground.

In some examples, the present disclosure provides a method formonitoring growth of a plant root through use of an electronic devicecomprising one or more processors, memory, and a plurality of sensorspositioned around the plant root, the method comprising: electricallycharging, at a sensor among the plurality of sensors, a first conductorplate configured to be disposed in soil from a power supply over a firstpredetermined time; electrically uncoupling the first conductor platefrom the power supply; extracting a signal response at the firstconductor plate over a second predetermined time; determining whether aportion of the signal response exceeds a threshold value, wherein a rootpresence is associated with a determination that the portion of thesignal response exceeded the threshold value; and storing a rootpresence indicator to the memory in accordance with the portion of thesignal response exceeding the threshold value. In certain examples, thepresent disclosure further provides for electrically grounding a secondconductor plate, wherein the second conductor plate is configured to bedisposed in soil and adjacent to and substantially parallel to the firstconductor plate.

In some examples, the present disclosure provides a non-transitorycomputer-readable storage medium comprising one or more programs forexecution by one or more processors of an electronic device, the one ormore programs including instructions which, when executed by the one ormore processors, cause the device to: electrically charge, at a sensoramong the plurality of sensors, a first conductor plate configured to bedisposed in soil from a power supply over a first predetermined time;electrically uncouple the first conductor plate from the power supply;extract a signal response at the first conductor plate over a secondpredetermined time; determine whether a portion of the signal responseexceeds a threshold value, wherein a root presence is associated with adetermination that the portion of the signal response exceeded thethreshold value; and store a root presence indicator to a memory inaccordance with the portion of the signal response exceeding thethreshold value. In certain examples, the present disclosure furtherprovides for electrically grounding a second conductor plate, whereinthe second conductor plate is configured to be disposed in soil andadjacent to and substantially parallel to the first conductor plate.

In some examples, the present disclosure provides a device formonitoring growth of a plant root, comprising: a cage structure suitablefor arrangement around the plant root; a plurality of root sensorsaffixed to the cage structure, wherein each root sensor of the pluralityis configured to detect the presence of the plant root; one or moreprocessors configured to receive data from the plurality of rootsensors; and a power source coupled to the one or more processors andthe plurality of root sensors.

In some examples, the present disclosure provides a non-transitorycomputer-readable storage medium comprising one or more programs forexecution by one or more processors of an electronic device, the one ormore programs including instructions which, when executed by the one ormore processors, cause the device to: receive data representing an inputfrom a root sensor of a plurality of root sensors, wherein the input isfrom a plant root of a plant in a soil location, and wherein theplurality of root sensors is positioned around the soil location; anddetermine a growth characteristic of the plant root based on the data.

In some examples, the present disclosure provides a method formonitoring growth of a plant root by a device comprising one or moreprocessors and a plurality of root sensors positioned around the plantroot, the method comprising: receiving data representing an input from aroot sensor of the plurality, wherein the input is from the plant root;and determining a growth characteristic of the plant root based on thedata.

In some examples, the present disclosure provides a device comprising: aplurality of root sensors; one or more processors; a memory; and one ormore programs, wherein the one or more programs are stored in the memoryand configured to be executed by the one or more processors, the one ormore programs including instructions for: receiving data representing aninput from a root sensor of the plurality, wherein the input is from aplant root; and determining a growth characteristic of the plant rootbased on the data.

In some examples, the present disclosure provides a method formonitoring growth of a plant root, comprising: positioning a pluralityof root sensors around a soil location; planting a seed in the soillocation; after the seed has grown into a plant having a plant root,receiving data representing an input from a root sensor of theplurality, wherein the input is from the plant root; and determining agrowth characteristic of the plant root based on the data.

In some examples, the present disclosure provides a method formonitoring growth of a plant root, comprising: positioning a pluralityof root sensors around a soil location, wherein a plant producing aplant root is planted in the soil location; receiving data representingan input from a root sensor of the plurality, wherein the input is fromthe plant root; and determining a growth characteristic of the plantroot based on the data.

In some examples, the present disclosure provides a method for selectinga plant for breeding based on a root growth characteristic, comprising:positioning a plurality of root sensors around a soil location; plantinga seed in the soil location; after the seed has grown into a planthaving a plant root, receiving data representing an input from a rootsensor of the plurality, wherein the input is from the plant root;determining a root growth characteristic of the plant root based on thedata; and selecting the plant for breeding based on the determined rootgrowth characteristic.

In some examples, the present disclosure provides a method fordetermining an effect of a plant-microbe interaction on a root growthcharacteristic, comprising: positioning a plurality of root sensorsaround a soil location; planting a first seed in the soil location;inoculating the soil location with a first microbe or community ofmicrobes; after the first seed has grown into a first plant having afirst plant root, and after a plant-microbe interaction is establishedbetween the first plant and the first microbe: receiving datarepresenting an input from a root sensor of the plurality, wherein theinput is from the first plant root; determining a first root growthcharacteristic of the first plant root based on the data; determining areference root growth characteristic of a reference plant root from areference plant of the same species as the first plant; and determiningthe effect of the plant-microbe interaction on the first root growthcharacteristic by comparing the first root growth characteristic to thereference root growth characteristic.

In some examples, the present disclosure provides a method fordetermining an effect of a plant-microbe interaction on a root growthcharacteristic, comprising: positioning a plurality of root sensorsaround a soil location; inoculating a first seed with a first microbe orcommunity of microbes; planting the first seed in the soil location;after the first seed has grown into a first plant having a first plantroot, and after a plant-microbe interaction is established between thefirst plant and the first microbe or community of microbes: receivingdata representing an input from a root sensor of the plurality, whereinthe input is from the first plant root; determining a first root growthcharacteristic of the first plant root based on the data; determining areference root growth characteristic of a reference plant root from areference plant of the same species as the first plant; and determiningthe effect of the plant-microbe interaction on the first root growthcharacteristic by comparing the first root growth characteristic to thereference root growth characteristic.

In some examples, the present disclosure provides a method formonitoring a soil organism, comprising: positioning a plurality of rootsensors around a soil location; planting a seed in the soil location;after the seed has grown into a plant having a plant root, and after thesoil organism has invaded the soil location, receiving data representingan input from a root sensor of the plurality; based on the data,determining whether the input is from the plant root or the soilorganism; and in accordance with a determination that the input is fromthe soil organism: monitoring the soil organism based on the data.

In some examples, the present disclosure provides a method formonitoring a soil organism, comprising: positioning a plurality of rootsensors around a soil location, wherein a plant having a plant root isplanted in the soil location, and wherein the soil organism has invadedthe soil location; receiving data representing an input from a rootsensor of the plurality; based on the data, determining whether theinput is from the plant root or the soil organism; and in accordancewith a determination that the input is from the soil organism:monitoring the soil organism based on the data.

It is to be understood that one, some, or all of the properties of thevarious examples described above and herein may be combined to formother examples of the present invention. These and other aspects of theinvention will become apparent to one of skill in the art. These andother examples of the invention are further described by the detaileddescription that follows.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the various described examples, referenceshould be made to the description below, in conjunction with thefollowing figures in which like reference numerals refer tocorresponding parts throughout the figures.

FIG. 1 is a diagram illustrating an example of a non-invasive rootphenotyping device.

FIGS. 2A and 2B are diagrams illustrating a top-view and an ISO-view ofa non-invasive root phenotyping device with conductor plates.

FIGS. 3A and 3B are diagrams illustrating an example of cross-sectionsof conductor plates tilted at oblique angle with respect to the base ofa root.

FIGS. 4A and 4B are circuit diagrams illustrating an example of a rootcontact sensor configured to determine whether a root is in contact withthe root conductor plate.

FIGS. 5A-5C are diagrams illustrating an example of a non-invasive rootphenotyping device with a plurality of conductor plates surrounding aplant at various stages of growth of a plant root system over time.

FIG. 6A is a diagram illustrating a side-view of a portion of a sensorarray for a non-invasive root phenotyping device with a plurality ofparallel conductor plates.

FIG. 6B is a diagram illustrating an ISO-view of a non-invasive rootphenotyping device with a portion of sensor array and a plurality ofparallel conductor plates trellised between circular supports.

FIGS. 7A and 7B are circuit diagrams illustrating an example of a rootproximity sensor in an instance where a root is absent from betweenfirst conductive plate and the second conductor plate.

FIGS. 8A and 8B are circuit diagrams illustrating an example of a rootproximity sensor in an instance where a root is between the firstconductive plate and the second conductor plate.

FIGS. 9A and 9B are circuit diagrams illustrating an example of a rootproximity sensor configured to determine whether a root is between thefirst conductive plate and the second conductor plate at instances whena root impinges on at least one conductor plate.

FIGS. 10A-10C are diagrams illustrating an example of a non-invasiveroot phenotyping device with a plurality of proximity sensorssurrounding a plant at various stages of growth of a plant root systemover time.

FIG. 11 is a diagram illustrating an ISO-view of a non-invasive rootphenotyping device with a proximity sensor array with a plurality ofproximity sensors trellised on a stake.

FIG. 12 is a conceptual data flow diagram illustrating the data flowbetween different means/components at a root phenotyping device.

FIG. 13 is a flow diagram of a plant phenotyping device with a pluralityof sensors to detect roots and determine root traits.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well-known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Examples of detecting roots for monitoring growth of a plant root willnow be presented with reference to various electronic devices andmethods. These electronic devices and methods will be described in thefollowing detailed description and illustrated in the accompanyingdrawing by various blocks, components, circuits, steps, processes,algorithms, etc. (collectively referred to as “elements”). Theseelements may be implemented using electronic hardware, computersoftware, or any combination thereof. Whether such elements areimplemented as hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

By way of example, an element, any portion of an element, or anycombination of elements may be implemented using one or more processors.Examples of processors include microprocessors, microcontrollers,graphics processing units (GPUs), central processing units (CPUs),application processors, digital signal processors (DSPs), reducedinstruction set computing (RISC) processors, systems on a chip (SoC),baseband processors, field programmable gate arrays (FPGAs),programmable logic devices (PLDs), state machines, gated logic, discretehardware circuits, and other suitable hardware configured to perform thevarious functionality described throughout this disclosure. One or moreprocessors in the processing system may execute software. Software shallbe construed broadly to mean instructions, instruction sets, code, codesegments, program code, programs, subprograms, software components,applications, software applications, software packages, routines,subroutines, objects, executables, threads of execution, procedures,functions, etc., whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise.

Accordingly, in one or more examples, the functions described may beimplemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media may include transitory or non-transitorycomputer storage media for carrying or having computer-executableinstructions or data structures stored thereon. Both transitory andnon-transitory storage media may be any available media that can beaccessed by a computer as part of the processing system. By way ofexample, and not limitation, such computer-readable media can comprise arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of theaforementioned types of computer-readable media, or any other mediumthat can be used to store computer executable code in the form ofinstructions or data structures that can be accessed by a computer.Further, when information is transferred or provided over a network oranother communications connection (hardwired, wireless, cellular, orcombination thereof) to a computer, the computer or processing systemproperly determines the connection as a transitory or non-transitorycomputer-readable medium, depending on the particular medium. Thus, anysuch connection is properly termed a computer-readable medium.Combinations of the above should also be included within the scope ofthe computer-readable media. Non-transitory computer-readable mediaexcludes signals per se and the air interface.

The present disclosure provides for an electronic device to detectand/or monitor the growth of a plant root. The electronic deviceincludes a support structure (e.g., cage structure) suitable forarrangement adjacent to the soil location. The electronic device furtherincludes a plurality of electronic sensors trellised to the supportstructure. Some of the plurality of electronic sensors are root contactsensors and some are root proximity sensors. The root contact sensorincludes a switch electrically coupled to a first conductor plate (e.g.,contact sensor), a signal extractor (e.g., voltage divider, analog todigital converter), and a power supply (e.g., voltage or currentsource). The switch is configured to electrically couple the powersupply to the first conductor plate in a first mode and electricallycouple the signal extractor to the first conductor plate in a secondmode.

In the second mode, the signal extractor receives a signal response fromthe first conductor plate after being charged by the power source in thefirst mode. A microcontroller receives signal response and compares itwith baseline signal responses stored in memory. In instances where aroot is not physically touching the first conductor plate, the signalresponse from the first conductor plate is characteristic of thebaseline signal response for no root impinging on the first conductorplate. In instances where a root is physically touching the firstconductor plate, the signal response from the first conductor plate ischaracteristic of the baseline signal response for a root impinging onthe first conductor plate.

The root proximity sensor includes a first conductor plate and a secondconductor plate, which is electrically coupled to ground. The proximitysensor is a switch electrically coupled to a first conductor plate, asignal extractor (e.g., voltage divider, analog to digital converter),and a power supply (e.g., voltage or current source). The switch of theproximity sensor is configured to electrically couple the power supplyto the first conductor plate in a first mode and electrically couple thesignal extractor to the first conductor plate in a second mode.

For the root proximity sensor, the first conductor plate and the secondconductor plate arc substantially parallel and electrically coupledthrough the impedance of the soil. Perturbations in the impedance in thesoil between the first conductor plate and the second conductor platecause a signal response at the first conductor plate when the switch isin the second mode. A microcontroller receives the signal response fromthe signal extractor and compares it with baseline signal responsesstored in memory. In instances where a root is not physically betweenthe first conductor plate and the second conductor plate, the signalresponse from the first conductor plate is characteristic of thebaseline signal response for no root between the first conductor plateand the second conductor plate. In instances where a root is physicallybetween the first conductor plate and the second conductor plate, thesignal response from the first conductor plate is characteristic of thebaseline signal response for a root between the first conductor plateand the second conductor plate. In instances where a root is physicallytouching the first conductor plate, the signal response from the firstconductor plate is characteristic of the baseline signal response for aroot impinging on the first conductor plate.

The electronic sensors and devices of the present disclosure implementtechniques of non-invasive root phenotyping, such as the techniques formonitoring growth of a plant root, techniques for selecting a plant forbreeding based on a root growth characteristic, techniques fordetermining an effect of a plant-microbe interaction on a root growthcharacteristic, and/or techniques for monitoring a soil organism. Thesetechniques described herein provide for monitoring of plant root growthin situ while the plant is growing, provide for a higher resolution ofmonitoring of RSA than existing devices (e.g., mini-rhizotron), andprovide for a low-cost solution that is suitable for field use withminimal interference to plant growth.

FIG. 1 is a diagram illustrating an example of a non-invasive rootphenotyping device 100. The root phenotyping device 100 includes asupport structure suitable for arrangement in a soil location adjacent aplant 140. In this example, the support structure is a cage structure120 with top circular support 122A, middle circular supports 122B, andbottom circular supports 122C vertically connected to extended verticalsupport 114 and vertical supports 110 that form a backbone for thesupport structure.

It is contemplated that additional circular supports 122A, 122B, 122Ccan be added to a desired cage structure 120. For example, a cagestructure can include 1 or more, 2 or more, 3 or more, 4 or more, 5 ormore, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, 11 ormore, or 12 or more, etc. circular supports 122A, 122B, 122C. The numberof circular supports 122A, 122B, 122C to be used can be influenced by,for example, a desired spacing and/or density of the cage circularsupports 122A, 122B, 122C; a size, shape, and/or complexity of the RSAto be monitored; the shape and/or configuration of the device; a numberof inputs that may be accommodated by a microcontroller of the presentdisclosure; and so forth Likewise, the cage structure 120 can be anauger or include a helical blade affixed to the cage structure 102 tofacilitate burrowing the cage structure 120 into the soil around theplant 140.

In some examples, the cage structure 120 is made from any material thatresists deformation upon insertion into a desired soil type withoutaffecting the health and growth of the plant 140. For example, the cagestructure 120 material can be metals (e.g., galvanized steel, stainlesssteel), plastic (e.g., bioplastics), and the like. In some examples, thecage structure 120 is made from biodegradable and/or compostablematerial such as polylactic acid (PLA), poly-3-hydroxybutyrate (PHB),polyhydroxyalkanoates (PHA), and the like. In some instances, a 3-Dprinter can be utilized to construct the cage structure 120 using asuitable thermoplastic (e.g., PLA, etc.). In some instances, the cagestructure 120 can be injected molded using a suitable thermoplastic(e.g., PLA, etc.).

The root phenotyping device 100 further includes a plurality ofconductor plates 126 affixed to the support structure (e.g., cagestructure 120). For example, the plurality of conductor plates 126 canbe trellised to a top circular support 122A, a middle circular support122B, and a bottom circular support 122C, as depicted in FIG. 1. In someinstances, the plurality of conductor plates 126 can be trellised to theextended vertical support 114 and vertical supports 110 that providesfor a relatively fixed position during insertion into a soil locationand subsequent operation. In some instances, one or more of theplurality of conductor plates 126 can be provided on a mesh andpositioned between the vertical supports 110 and the circular supports122A, 122B, 122C. Each of the plurality of conductor plates 126 iselectrically coupled (e.g., via wired interconnects) to a controller 130(e.g., microcontroller) that is configured to determine whether a rootphysically touches a contact sensor.

As depicted in FIG. 1, the root phenotyping device 100 includes anelectrode 138 that is electrically coupled to the controller 130.Electrode 138 is an electrically conductive rod that is inserted intothe soil to provide a good electrical coupling to earth ground. In someexamples, the electrode 138 is made from a non-reactive metal (e.g.,stainless steel) or a highly conductive metal (e.g., copper).

In some examples, at least one of the plurality of conductor plates 126is a part of a root sensor that is configured to detect a change inimpedance between soil and a root caused by physical contact with a root142 of plant 140. In some instances, the root sensor detects a change incapacitance between the soil and at least one of the plurality ofconductor plates 126 once a root 142 physically contacts at least one ofthe plurality of conductor plates 126. In some instances, the rootsensor detects a change in resistance between the soil and at least oneof the plurality of conductor plates 126 once a root 142 physicallycontacts the at least one of the plurality of conductor plates 126.

As depicted in FIG. 1, controller 130 includes a communications unit(e.g., antenna 108, I/O port for cable 106) configured to transmitsensory data to a mobile device 154 (e.g., smart phone, tablet PC). Insome instances, the communications unit can transmit sensory data overcable 106 to a mobile device 154. In some instances, cable 106 is aserial cable with appropriate connectors to interface with thecommunication unit of controller 130 and the mobile device 154. In suchan instance, the communication unit includes circuitry (e.g., serialtransceiver, etc.) to transmit and receive serial communications. Insome examples, the communications unit can include an antenna 108 andcircuitry configured to transmit sensory data wirelessly (e.g.,Bluetooth, WiFi) to mobile device 154. In such an instance, thecommunication unit includes circuitry (e.g., Bluetooth transceiver, WiFitransceiver, etc.) to transmit and receive serial communications viawireless protocols. In some examples, the communications unit caninclude an antenna 108 and circuitry configured to transmit sensory dataover a cellular network (e.g., 3G, 4G, LTE) to cellular tower or mobiledevice 154. In such an instance, the communication unit includescircuitry (e.g., 3G transceiver, 4G transceiver, LTE transceiver, etc.)to transmit and receive communications via cellular protocols.

The root phenotyping device 100 can also include one or more sensors(e.g., soil sensor 134, ambient sensor 136) associated with any desiredaspect of plant 140, the soil location, and/or one or more above-groundconditions at or near the soil location. In general, the soil sensor 134is located within the soil or at the air/soil interface, and the ambientsensor 136 is located above the soil or at the air/soil interface. Forexample, the soil sensor 134 can be configured to determine one or morenutrient levels (e.g., phosphorus, nitrogen, oxygen, soil humidity,temperature, moisture, pH, etc.) of the soil situated at or near theplant location. In some instances, soil sensor 134 is a nutrient sensor.In some instances, soil sensor 134 is a soil humidity sensor, a moisturesensor, or a temperature sensor.

The ambient sensor 136 is configured to determine one or moreenvironmental/ambient conditions above ground. In some examples, theambient sensor 136 is configured to determine one or more environmentalconditions (e.g., humidity, temperature, light, etc.) associated withthe plant. In some instances, the ambient sensor 136 is a temperaturesensor or a humidity sensor. In some instances, the ambient sensor 136is a rain sensor or a light sensor. Both the soil sensor 134 and theambient sensor 136 provide in situ information regarding localized fieldlocations (e.g., related to soil desiccation and/or fertilizerretention). This information assists breeders and growers in targetingirrigation and/or fertilizer to specific field locations, which providescost and energy savings.

Power provided to controller 130 of the root phenotyping device 100includes one or more power sources. For example, as depicted in FIG. 1,the root phenotyping device 100 can include solar cell 132 affixed toextended vertical support 114 to provide electrical power to controller130. Other suitable power sources can include one or more solar cells,one or more batteries, or any combination thereof (e.g., solar cell 132configured to charge a battery). In some examples, controller 130 of thepresent disclosure has both active and power-down modes, which providefor modulation of power consumption.

FIGS. 2A and 2B are diagrams illustrating a top-view and an ISO-view ofa non-invasive root phenotyping device 100 with conductor plates 126. Asdepicted in FIG. 2B, the circular supports 122A, 122B, 122C are arrangedparallel to and separated from each other along the z-axis. The circularsupport 122A corresponds to a top ring of cage structure 120 (e.g.,first row), circular supports 122B correspond to a middle ring of cagestructure 120 (e.g., first row), and circular support 122C correspondsto a bottom ring of cage structure 120 (e.g., third row). Each circularsupport 122A, 122B, 122C includes a plurality of conductor plates 126that are arranged at a fixed spatial location on the x-y plane on oraround the surface of the ring. Each root sensor is designated alocation with a distinct identifier that is spatially mapped tocontroller 130. For example, the plurality of conductor plates 126 aredesignated 126A1-126A8, 126B1-126B8, 126C1-126C8 etc., where the “A,”“B,” and “C” corresponds to rows and the “1”-“8” corresponds to columns.The physical location for each designated electronic sensor 126A1-126A8,126B1-126B8, 126C1-126C8 can easily be determined and spatially mappedto the controller 130.

In some examples, one or more of the supports (e.g., vertical supports110 and extended vertical support 114) are removable (e.g., verticalsupport 114). As depicted in FIG. 2B, supports 110 have been removed. Insome examples, extendible vertical support 114 is a removable and/orextendible rod that slides into the cage structure 120. In such aninstance, the extendible vertical support 114 elements affixed theretocan be removed from the soil and the rest of root phenotyping device100. Further, the removable aspect facilitates microcontroller 130,solar panel 132, soil sensor 134, and ambient sensor 136 to be removed(e.g., at the end of a growing season). It should be appreciated thateach component, once removed, can be reused for another plant or growingseason.

It should be appreciated that the support structure can be constructedto accommodate other spatially viable positions for conductor plates126. For example, in some instances the support structure can be atapered such that the column positions of the conductor plates 126 in anadjacent ring are vertically skewed (e.g., positioned in a different x,y, and z position). In some instances, the support structure can contourto the surface of a sphere, cone, cylinder, etc.

FIGS. 3A and 3B are diagrams illustrating an example of cross-sectionsof conductor plates 126 tilted at oblique angles with respect to thebase of a root 142. The root sensor is situated at a slant from the +ydirection (e.g., y axis) toward the +z direction (e.g., z axis) withrespect to a lateral (x-y plane) base of the root 142. Thisconfiguration is less invasive to the plant 140, as the roots 142 arenaturally angled with respect to the base of the root 142. Conceptually,the oblique angle (e.g., θ₁, θ₂) is slight angled downward (e.g., towardthe z-axis) from the root angle (e.g., α₁, α₂). This provides for agreater surface area along the point of contact 342 with the conductorplates 126. For example, the root 142 depicted in FIG. 3A has shallowroots with a root angle α₁ from the lateral direction (e.g., y axis),and the conductor plate 126 is situated at an angle of θ₁, which isgreater than the root angle α₁. This configuration reduces theobstruction area of the root 142 while providing a greater surface areafor the root to grow along the surface 342 of the conductor plate 126.Likewise, the root 142 depicted in FIG. 3B has shallow roots with a rootangle α₂ from the lateral direction (e.g., y axis), and the conductorplate 126 is situated at an angle of θ₂, which is greater than the rootangle α₂.

In general, the root angle α₂ depicted in FIG. 3B is for deep roots thatare situated below the shallow roots with a root angle α₁ depicted inFIG. 3A. As such, the support structure (e.g., cage structure 120) ofphenotyping device 100 can affix the plurality of conductor plates 126at various oblique angles. In some examples, the oblique angles of theconductor plate 126 vary with depth (e.g., z-axis). In some examples,the oblique angles of conductor plate 126 near the surface are less thanor equal to the oblique angles of conductor plate 126 situatedvertically lower. In some examples, the oblique angles of conductorplate 126 near the surface are greater than the oblique angles ofconductor plate 126 situated vertically lower.

As depicted in FIGS. 3A and 3B the plurality of conductor plates 126 areaffixed to support structure 325. The support structure can bepositioned between the vertical supports 110 (or the extended verticalsupport 114) and the lateral supports (e.g., circular supports 122A,122B, 122C). The support structure can be made from biodegradable and/orcompostable material such as cotton, bamboo, soy protein fabric, wool,tencel, wood, polylactic acid (PLA), poly-3-hydroxybutyrate (PHB),polyhydroxyalkanoates (PHA), and the like. The support structure can bemade from a non-reactive metal (e.g., stainless steel) or a highlyconductive metal (e.g., copper, galvanized steel, etc.). It should beappreciated that conductor plates 126 are electrically insulated fromthe non-reactive metal or highly conductive metal. In some examples, thesupport structure 325 is mesh that can be made from twines (e.g., cords,threads, or wire) surrounding open spaces. The open spaces provide apath for the roots 142 to grow without obstruction.

FIGS. 4A and 4B are circuit diagrams illustrating an example of a rootcontact sensor 400 configured to determine whether a root 142 is incontact with the root conductor plate 126. The root contact sensor 400includes a switch 406 electrically coupled to a first conductor plate452, a power supply 402, a signal extractor 404, and a microprocessor410. The first conductor plate 452 is an electrically conductive platesituated in the soil. The first conductor plate 452 can be made from anon-reactive metal (e.g., stainless steel) or a highly conductive metal(e.g., copper, galvanized steel, etc.). As depicted in FIG. 1, anelectrode 138 is inserted into the soil to provide a good electricalcoupling to earth ground. As such, the soil impedance 416 provides aconduit for charges to flow from the first conductor plate 452 throughthe soil to an electrode 138. Charge applied to the first conductorplate 452 can build up or dissipate depending on the electricalproperties (e.g., impedance 416) of the soil. For example, for wet saltysoils the impedance can be low (e.g., resistivity ˜10 Ω-m), and for drysoils the impedance can be high (e.g., resistivity ˜1 kΩ-m). Likewise,for very dry soils the impedance can be even higher (e.g., resistivityranging between 1 kΩ-m to 10 kΩ-m).

It should be appreciated that earth ground and chassis ground can havedifferent voltage potentials (e.g., V_(Earth)≠V_(Chassis)). That is,even for instances where an electrical wire shorts the chassis ground toearth ground, the electrical wire connection has a non-zero lineimpedance 422. In some instances of poor grounding, the electrode 138can be positioned on the chassis ground rather than the earth grounddepicted in FIGS. 4A and 4B.

The switch 406 is configured to switch between a first mode and a secondmode. In the first mode, the power supply 402 is enabled to provide anelectrical charge to the first conductor plate 452. As depicted in FIG.4A, the power supply 402 is electrically coupled to the first conductorplate 452. In this configuration, a charge (e.g., voltage potential)builds up due to the non-zero impedance (e.g. resistivity) between thefirst conductor plate 452 and the electrode 138. In the second mode, thesignal extractor 404 is enabled to capture the signal response. In thisconfiguration, the power supply 402 is electrically uncoupled from thefirst conductor plate 452, and the signal extractor 404 is electricallycoupled to the first conductor plate 452. In turn, the charge dissipatesover time as electrons flow from the earth ground of the electrode 138through the soil to the first conductor plate 452.

In some examples, the switch 406 can be a multiplexor that iselectrically coupled to and controlled by the microcontroller 410. Amultiplexer facilitates electrical coupling to a plurality of conductorplates 126 to share outputs (e.g., electrical coupling to power supply402 and signal extractor 402). For example, microcontroller 410 of theroot phenotyping device 100 can include control lines 420 to control theswitching of a multiplexor (e.g., switch 406) that electrically couplesa plurality of conductor plates 126 to a single power supply 402 or thatelectrically couples a plurality of conductor plates 126 to a singlesignal extractor 404. In some examples, the switch 406 is a relay thatis electrically coupled to and controlled by the microcontroller 410.

The signal extractor 404 is configured to extract (e.g., capture) asignal response at the first conductor plate 452. In the second mode ofthe switch 406, the signal extractor 404 captures the voltage at thefirst conductor plate 452 over time as the charge dissipates, whichyields a signal response proportional to electrical properties of thesoil (e.g., soil impedance 416). In some examples, the signal extractoris a voltage divider, where the extracted voltage is a ratio ofimpedances (e.g., v₀=Z₁/(Z₁+Z₂)×v_(in)). In some examples, signalextractor 404 is an analog-to-digital converter (ADC) configured toconvert the signal response to digital equivalents. In such an example,the ADC can be configured to digitally capture the signal response. Itshould be appreciated that the extracted signal (e.g., voltage) from theADC is with respect to the chassis ground of controller 130, which iscommon to a plurality of conductor plates 126.

In some examples, signal extractor 404 can be configured to store theextracted signal response in computer readable medium/memory 408 atpredetermined (e.g., periodic) intervals. For example, in some instancesthe signal extractor 404 can store a signal response every five minutesthat can be aggregated or retrieved for further processing.

The root contact sensor 400 can further include a microcontroller 410configured to receive a raw response signal from the signal extractor404. As depicted in FIG. 4A, the microcontroller 410 includes a signalprocessor 412 that receives and conditions the raw response signalsuitable for comparison. For example, the raw response signal can havehigh-frequency noise and the signal processor 412 can apply a low-passfilter (e.g., Butterworth filter, Chebyshev filter, Cauer filter, etc.)to condition the signal response.

Signal processor 412 is also configured to retrieve a baseline signalresponse from computer readable medium/memory 408 and compare portionsof the signal response to portions of the baseline signal response. Abaseline signal response is a signal response of the root contact sensor400 under conditions similar to the conditions at the site of the plant.For example, in one instance, the soil sensor 134 can detect theresistivity of the soil at a designated temperature. In turn, the signalprocessor 412 can retrieve from the computer readable medium/memory 408(e.g., query a database) a baseline response signal for a soil that hassimilar resistivity and temperature to compare with the conditionedsignal response. It should be appreciated that additional soilcharacteristics can also be applied when determining a baseline responsesignal such as salinity, aeration, etc. In some examples, the soilsensor 134 is a soil humidity sensor or a temperature sensorelectrically coupled to the microcontroller 410. In some examples, theambient sensor 136 is a humidity sensor or a temperature sensorelectrically coupled to the microcontroller 410.

In some examples, the baseline response signal is determined fromaggregated response signals from the conductor plates 126. For example,in the early stages of plant growth (e.g., prior to root development),signal response samples can be stored and aggregated based on the soilcharacteristics. In general, the baseline signal response isrepresentative of a signal response of the conductor plate 126 in soilwithout a root 142 that is in contact with the first conductor plate 452under similar conditions (e.g., salinity, resistivity, temperature,aeration, etc.).

The microcontroller 410 includes a determinator 414 that compares theconditioned signal response to the baseline signal response to determinewhether a root 142 is present. As depicted in FIG. 4A, root 142 is inproximity to the first conductor plate 452, but it does not physicallycontact conductor plate 354. As such, the charge on the first conductorplate 452 is not distributed on the root 142, which provides additionalelectrical paths (e.g., root impedance 418) for dissipation. Instead,the charge is confined to the first conductor plate 452 for dissipationthrough the soil (e.g., soil impedance) to the first conductor plate452. The dissipation of the charge has a characteristic signal responseprofile that is sufficiently similar to a baseline signal response.

The determinator 414 compares the conditioned signal to the baselinesignal. In the example depicted in FIG. 4A, the determinator 414determines that no root 142 is detected because the conditioned responsesignal is sufficiently similar to the baseline signal response (e.g.,signal response without a root present). In some examples, determinator414 is a digital comparator configured to determine whether thedifference between portions of the conditioned signal response andportions of the baseline signal response exceeds a threshold value. Inone instance, a portion of the baseline signal response can be a peak(e.g., max or relative max value) that corresponds to a peak (e.g., maxor relative max value) of the conditioned signal response. In such aninstance, the determinator 414 can determine that no root is detectedfor a peak of the conditioned signal response that exceeds a thresholdvalue (e.g., 90% of peak from baseline signal).

As depicted in FIG. 4B, root 142 is in physical contact with the firstconductor plate 452. As such, the charge on the first conductor plate452 is distributed throughout root 142. The distribution of chargeprovides an additional electrical path (e.g., root impedance 418) fordissipation. In this example, the charge is no longer confined to thefirst conductor plate 452 for dissipation through the soil (e.g., soilimpedance 416 path). Instead, the charge is distributed along the root142 (e.g., root impedance 416 path), which changes the characteristicsignal response profile from the baseline signal response.

The determinator 414 compares the conditioned signal to the baselinesignal, and the determinator 414 determines that electricalperturbations from the root 142 in physical contact with the firstconductor plate 452 produce a response signal dissimilar to the baselinesignal response (e.g., signal response without a root present). In someexamples, determinator 414 is a digital comparator configured todetermine whether the difference between portions of the conditionedsignal response and portions of the baseline signal response does notexceed a threshold value. For instance, the determinator 414 candetermine that a root is detected when a peak of the response signaldoes not exceed a threshold value (e.g., 90% of peak from baselinesignal). That is, a root presence is associated with a determinationthat the signal response exceeded the threshold value. It should beappreciated that a baseline signal response can include a signalresponse of a root in physical contact with the first conductor plate452. In such an instance, the determinator 414 can determine that a rootis detected when the response signal is similar to the baseline signal.

As depicted in FIGS. 4A and 4B, the root contact sensor 400 can furtherinclude a computer readable medium/memory 408 electrically coupled tothe microcontroller 410. The computer readable medium/memory 408 isconfigured to store data associated with the signal extractor. In someexamples, the computer readable medium/memory 408 is RAM, ROM, EEPROM,and the like. The computer readable medium/memory 408 can include adatabase of baseline signal responses for various soil conditions at thesite of the plant such as resistivity, salinity, moisture content,temperature, aeration, aggregation (e.g., rocky, clay, sand), and thelike.

FIGS. 5A-5C are diagrams illustrating an example of a non-invasive rootphenotyping device 100 with a plurality of conductor plates 126 surrounda plant at various stages of growth of a plant root system over time500A, 500B, 500C. As depicted in FIGS. 5A-5C, the root phenotypingdevice 100 includes a plurality of conductor plates 126 affixed (e.g.,trellised) to cage structure 120 and are similar to the root phenotypingdevice 100 depicted in FIG. 1. At time 500A, seed 540 is planted in asoil at a specified location at a known depth. The root phenotypingdevice 100 is buried around soil location such that the location of seed540 is at or near an approximate center of cage structure 120. In someexamples, the root phenotyping device 100 can be buried prior to time500A depicted in FIG. 5A. For example, multiple root phenotyping devices100 can be installed along a row at an instance in time, and individualseeds 540 can be planted at or near the center of each root phenotypingdevice 100 at a later instance in time using an automated planter. Insome instances, root phenotyping device 100 can be buried after seed 540has been planted without interfering with the roots 142. For example,the root phenotyping device 100 can be buried while plant 140 is at astage in growth similar to that depicted in FIG. 5B.

FIG. 5B represents a later time than FIG. 5A, where the seed 540 hassprouted and has grown into a small plant with relatively small roots142 that emanate from the known planted location. In this instance, theroots 142 emanate from the plant 140 at the origin of where the seed 540had been planted in FIG. 5A. As depicted in FIG. 5B, the rootphenotyping device 100 does not detect a root 142 in contact with afirst conductor plate 452 because the roots do not touch the conductorplate 126.

FIG. 5C represents a later time than FIG. 5B, where the plant 140 andthe roots 142 have grown. In this instance, the roots 142 have grownsufficiently to contact various conductor plates 126 affixed to the topcircular structure 122A and the middle circular structure 122B. In thisinstance, the conductor plate 126B2 and conductor plate 126B8 are inphysical contact with a root 142. In turn, the extracted signal responseis conditioned and compared to a baseline signal response, and it isdetermined by the microcontroller 410 that a root 142 is in contact witha first conductor plate 452 at a location associated with conductorplate 126B2 and conductor plate 126B8 at a designated time (e.g.,timestamp).

In some instances, the conductor plates 126 have not detected a root 142below row 126B (e.g., no root at 126C, 126D, etc.). In such an instance,the root phenotyping devices 100 can determine the root approximategrowth rate (e.g., distance to conductor plate 126B2, 126B8 divided bythe time of initial detection) as well as the approximate depth of theroot system.

FIG. 6A is a diagram illustrating a side-view of a portion of a sensorarray 625 for a non-invasive root phenotyping device with a plurality ofparallel conductor plates 626. In this example, each parallel conductorplate 626 is designated a spatial location with a distinct identifierthat is mapped to controller 130. The plurality of parallel conductorplates 626 are designated 626A1-626A5, 626B1-626B5, 626C1-626C5 etc.,where the “A,” “B,” and “C,” correspond to rows and the “1”-“5”correspond to columns. From this mapping the controller 130 canspatially map a detected root 142.

It should be appreciated that the support structure can be constructedto accommodate other spatially viable positions for the parallelconductor plates 626. For example, in some instances the supportstructure can be tapered such that the column positions of the parallelconductor plates 626 in an adjacent circular structure are verticallyskewed (e.g., positioned in a different x, y, and z position). In someinstances, the support structure along with trellised sensor array 625can contour to a spherical shape, conical shape, cylindrical shape, etc.

As depicted in FIG. 6A, a parallel conductor plate 626 includes a firstconductor plate 452 adjacent to and substantially parallel to a secondconductor plate 654. The region between the first conductor plate 452and the second conductor plate 654 is filled with soil. As discussedsupra, the impedance between the first conductor plate 452 and thesecond conductor plate 654 can vary based on the electrical properties(e.g., impedance 416) of the soil, such as soil type (e.g., clay, sand,aggregate, etc.), moisture content, and nutrients (e.g., phosphate,nitrate, potassium, salts, etc.). As depicted in FIG. 6A, the firstconductor plate 452 and the second conductor plate 654 for each parallelconductor plates 626 are oriented laterally (e.g., along the y-axis). Insome examples, the first conductor plate 452 and/or the second conductorplate 654 for one or more electronic sensors can be tilted at obliqueangles with respect to the base of a root 142, as depicted in FIGS. 2Aand 2B. In some examples, the first conductor plate 452 and the secondconductor plate 654 for one or more electronic sensors can be positionedsidelong (e.g., along the z-axis).

It should be appreciated that the gap between the first conductor plate452 and the second conductor plate 654 can vary in distance and crosssectional area. In some examples, a gap between the first conductorplate 452 and the second conductor plate 654 has a cross sectional areaof less than or equal to about 1 cm². In some examples, a distancebetween the first conductor plate 452 and the second conductor plate 654is equal to or greater than about 1 mm.

FIG. 6B is a diagram illustrating an ISO-view of a non-invasive rootphenotyping device 600 with a portion of sensor array 625 with aplurality of parallel conductor plates 626 trellised between circularsupports 122A, 122B, 122C. In this example, the support structure is acage structure 120 with top circular support 122A (e.g., first row),middle circular support 122B (e.g., second row), and bottom circularsupports 122C (e.g., third row) vertically (e.g., along the z-axis)connected to extended vertical support 114, which forms a backbone forthe support structure. The circular supports 122A, 122B, 122C arearranged parallel and separate from each other along the z-axis.Although not depicted, the root phenotyping device 600 can includevertical supports 110 for additional support.

As depicted in FIG. 6B, a portion of sensor array 625 is situatedbetween the bottom circular support 122C and the middle circular support122B. Likewise, a duplicate of the portion of sensor array 625′ issituated between top circular support 122A and the middle circularsupport 122B. In some examples, a portion of sensor array 625, isextended around the circular supports 122A, 122B, 122C to enclose acylindrical surface around the plant 140. In some examples, a portion ofsensor array 625 is affixed to the circular section of the bottomcircular support 122C to enclose a bottom circular portion of thecylindrical section. In some examples, additional sensor arrays 625 areattached to one or more second circular supports outside the circularsupports 122A, 122B, 122C.

As in the example depicted in FIG. 1, the cage structure 120 ofnon-invasive root phenotyping device 600 is made from any material thatresists deformation upon insertion into a desired soil type withoutaffecting the health and growth of the plant 140. For example, the cagestructure 120 material is made from metal (e.g., galvanized steel,stainless steel), plastic (e.g., bioplastics), and the like. In someexamples, the cage structure 120 is made from biodegradable and/orcompostable material such as polylactic acid (PLA),poly-3-hydroxybutyrate (PHB), polyhydroxyalkanoates (PHA), and the like.In some instances, a 3-D printer can be utilized to construct the cagestructure 120 using a suitable thermoplastic (e.g., PLA, etc.). In someinstances, the cage structure 120 can be injected molded using asuitable thermoplastic (e.g., PLA, etc.).

Although vertical supports 110 are not depicted in FIG. 6A, it should beappreciated that, in some examples, the vertical supports 110 can beaffixed to the circular supports 122A, 122B, 122C to provide additionalstrength and rigidity to the non-invasive root phenotyping device 600Likewise, other components depicted in the non-invasive root phenotypingdevice 100 of FIG. 1 can be implemented in root phenotyping device 600.For example, it should be appreciated that examples of the non-invasiveroot phenotyping device 600 can include a solar cell 132, soil sensor134, ambient sensor 136, and the like.

FIGS. 7A and 7B are circuit diagrams illustrating an example of a rootproximity sensor 700 in an instance where a root 142 is absent frombetween a first conductive plate 452 and a second conductor plate 654.The root proximity sensor 700 includes a first conductor plate 452 and asecond conductor plate electrically coupled to ground (e.g., chassisground). The second conductor plate 654 is adjacent to the firstconductor plate 452 and substantially parallel to the first conductorplate 452. The first conductor plate 452 and the second conductor plateare electrically conductive plates situated in the soil, as depicted inFIG. 7A. The first conductor plate 452 and the second conductor plate654 can be made from a non-reactive metal (e.g., stainless steel) or ahighly conductive metal (e.g., copper, galvanized steel, etc.). In thisexample, an electrode 138 is inserted into the soil to provide a goodelectrical coupling to earth ground, as depicted in FIG. 1. As such, thesoil impedance 416 provides a conduit for charges to flow from theconductor plate 654 through the soil to an electrode 138. Charge appliedto the first conductor plate 452 can build up or dissipate depending onthe electrical properties (e.g., impedance 416) of the soil.

It should be appreciated that earth ground and chassis ground can havedifferent voltage potentials (e.g., V_(Earth)≠V_(Chassis)). That is,even for instances where an electrical wire shorts the chassis ground toearth ground, the electrical wire connection has a non-zero lineimpedance 422. In some instances of poor grounding, the electrode 138can be positioned on the chassis ground rather than the earth grounddepicted in FIG. 7A.

The root proximity sensor 700 further includes a switch 406 electricallycoupled to the first conductor plate 452, a power supply 402, a signalextractor 404, and a microprocessor 410. The switch 406 is configured toswitch between a first mode and a second mode. In the first, mode thepower supply 402 is enabled to provide an electrical charge to the firstconductor plate 452. As depicted in FIG. 7A, the power supply 402 iselectrically coupled to the first conductor plate 452, and, as such, aslight charge (e.g., voltage potential) will build up due to thenon-zero soil impedance 416 (e.g., resistivity) between the firstconductor plate 452 and the second conductor plate 454, as well as thesoil impedance 416 (e.g., resistivity) between the first conductor plate452 and the electrode 138.

In the second mode, the signal extractor 404 is enabled to capture thesignal response. In this configuration, power supply 402 is electricallyuncoupled from the first conductor plate 452, and the signal extractor404 is electrically coupled to the first conductor plate 452. As such,the charge dissipates over time as electrons flow in the soil across thegap between the second conductor plate 654 and the first conductor plate452, as well as from the earth ground of the electrode 138 through thesoil to the conductor plate 654.

In some examples, the switch 406 can be a multiplexor that iselectrically coupled to and controlled by the microcontroller 410. Amultiplexer facilitates electrical coupling to a plurality of parallelconductor plates 626 (shown in FIG. 6A and 6B) to shared terminals(e.g., electrical coupling to power supply 402 and electrical couplingto signal extractor 402). For example, microcontroller 410 of the rootphenotyping device 100 can include control lines 420 to control theswitching of a multiplexor (e.g., switch 406) that electrically couplesa plurality of parallel conductor plates 626 to a single power supply402 or that electrically couples a plurality of parallel conductorplates 626 to a single signal extractor 404. In some examples, theswitch 406 is a relay that is electrically coupled to and controlled by(e.g., via control lines 420) the microcontroller 410.

The signal extractor 404 is configured to capture a signal response atthe first conductor plate 452. In the second mode of the switch 406, thesignal extractor 404 captures the voltage at the first conductor plate452 at instances in time as the charge dissipates, which yields atransient signal response proportional to electrical properties of thesoil (e.g., soil impedance 416). In some examples, the signal extractoris a voltage divider, where the extracted voltage is a ratio ofimpedances (e.g., v₀=Z₁/(Z₁+Z₂)×v_(in)). In some examples, signalextractor 404 is an ADC configured to convert the signal response todigital equivalents. In such an example, the ADC can be configured todigitally capture the signal response. It should be appreciated that thesignal (e.g., voltage) from the ADC is extracted with respect to thechassis ground of controller 130, which is common to a plurality ofparallel conductor plates 626.

In some examples, signal extractor 404 can be configured to store theextracted signal response in computer readable medium/memory 408 atpredetermined (e.g., periodic) intervals. For example, in some instancesthe signal extractor 404 can store a signal response every five minutesthat can be aggregated or retrieved for further processing.

The root proximity sensor 700 can further include a microcontroller 410configured to receive a raw response signal from the signal extractor404. As depicted in FIG. 7A, the microcontroller 410 includes a signalprocessor 412 that receives and conditions a response signal suitablefor comparison. For example, the raw response signal can havehigh-frequency noise. In such an instance, the signal processor 412 canapply a low-pass filter (e.g., Butterworth filter, Chebyshev filter,Cauer filter, etc.) to condition the signal response.

Signal processor 412 is also configured to retrieve one or more baselinesignal responses from computer readable medium/memory 408 and compareportions of the signal response to portions of the baseline signalresponse. A baseline signal response is a signal response of the rootproximity sensor 700 under conditions similar to the conditions at thesite of the plant. For example, in one instance, the soil sensor 134 candetect the resistivity of the soil at a designated temperature. In turn,the signal processor 412 can retrieve from the computer readablemedium/memory 408 (e.g., query a database), a baseline response signalfor a soil that has similar resistivity and temperature to compare withthe conditioned signal response. It should be appreciated thatadditional soil characteristics can also be applied when determining abaseline response signal such as salinity, aeration, etc. In someexamples, the soil sensor 134 is a soil humidity sensor or a temperaturesensor electrically coupled to the microcontroller 410. In someexamples, the ambient sensor 136 is a humidity sensor or a temperaturesensor electrically coupled to the microcontroller 410.

In some examples, the baseline response signal is determined fromaggregated response signals extracted from the plurality of parallelconductor plates 626. For example, in the early stages of plant growth(e.g., prior to root elongation), signal response samples can be storedand aggregated based on the soil characteristics. In general, thebaseline signal response is representative of a signal response of theparallel conductor plate 626 in soil without a root 142 between thefirst conductor plate 452 and the second conductor plate 654 undersimilar conditions (e.g., salinity, resistivity, temperature, aeration,etc.).

The microcontroller 410 includes a determinator 414 that compares theconditioned signal response to the baseline signal response to determinewhether a root 142 is present. As depicted in FIG. 7A, root 142 is inproximity to the first conductor plate 452 and the first conductor plate452 but is not in between the first conductor plate 452 and the secondconductor plate 654. In this instance, the root 142 is not polarizedwith electrons attracted to the charged first conductor plate 452 on oneside of the root 142 and electrons repelled from the charged firstconductor plate 452 on the opposite side of the root 142. As such, theimpedance of the soil (e.g., permittivity and permeability) remainssubstantially unchanged from soils without plant roots.

As depicted in FIG. 7A, the charge is confined to the first conductorplate 452 for dissipation through the soil (e.g., soil impedance).Consequently, the overall impedance of the soil between the firstconductor plate 452 and the second conductor plate 654 is thecapacitance of the soil C_(soil) in parallel with the overallcapacitance of the root C_(root), as depicted in FIG. 7B. In such anexample, the first conductor plate 452 will have a characteristic signalresponse profile that is sufficiently similar to a baseline signalresponse.

The determinator 414 compares the conditioned signal to the baselinesignal. In the example depicted in FIG. 7A, the determinator 414determines that no root 142 is detected between the first conductorplate 452 and the second conductor plate 654 because the conditionedresponse signal is sufficiently similar to the baseline signal response(e.g., signal response without a root present). In some examples,determinator 414 is a digital comparator configured to determine whetherthe difference between portions of the conditioned signal response andportions of the baseline signal response exceeds a threshold value. Inone instance, a portion of the baseline signal response can be a peak(e.g., max or relative max value) that corresponds to a peak (e.g., maxor relative max value) of the conditioned signal response. In such aninstance, the determinator 414 can determine that no root is detectedfor a peak of the conditioned signal response that exceeds a thresholdvalue (e.g., 90% of peak from baseline signal).

As depicted in FIGS. 7A and 7B, the root proximity sensor 700 caninclude a polarity switch 706 electrically coupled to switch 406, thefirst conductor 452 and the second conductor 654. The polarity switch isconfigured to provide a second configuration that exchanges electricalcoupling between the first conductor plate 452 and the second conductorplate 654. That is, the polarity switch 706 reconfigures the electricalcoupling such that the first conductor plate 452 is electrically coupledto ground (e.g., chassis ground), and the second conductor plate 654 iselectrically coupled to the power supply 402 through the switch 406 inthe first mode or the second conductor plate 654 is electrically coupledto signal extractor 404 through the switch 406 in the second mode.

As depicted in FIGS. 7A and 7B, the root proximity sensor 700 canfurther include a computer readable medium/memory 408 electricallycoupled to the microcontroller 410. The computer readable medium/memory408 is configured to store data associated with the signal extractor. Insome examples, the computer readable medium/memory 408 is RAM, ROM,EEPROM, and the like. The computer readable medium/memory 408 caninclude a database of baseline signal responses for various soilconditions at the site of the plant such as resistivity, salinity,moisture content, temperature, aeration, aggregation (e.g., rocky, clay,sand), and the like.

FIGS. 8A and 8B are circuit diagrams illustrating an example of a rootproximity sensor 700 in an instance where a root 142 is between thefirst conductive plate 452 and the second conductor plate 654. Theproximity sensor 700 has the same components as described in FIGS. 7Aand 7B above. As depicted in FIG. 8A, the root 142 is situated betweenthe first conductor plate 452 and the second conductor plate 654, but itis not in contact with either the first conductor plate 452 or thesecond conductor plate 654. With the root 142 situated between the firstconductor plate 452 and the second conductor plate 654, the root 142becomes polarized with electrons attracted to the positively chargedfirst conductor plate 452 on the side of the root 142 nearest the firstconductor plate 452, and electrons are repelled from the negativelycharged second conductor plate 654 on the opposite side of the root 142nearest the second conductor plate 654. In turn, the polarized root 142changes the overall impedance characteristics. More specifically, theeffective impedance characteristics of a portion of the soil between thefirst conductive plate 452 and the second conductor plate 654 without aroot 142 (e.g., between d_(s)) remains unchanged, whereas the effectiveimpedance characteristics of a portion of the soil changes between thefirst conductive plate 452 and the second conductor plate 654 with aroot 142 (e.g., between d_(r)).

In this instance, the portion of the soil between the between the firstconductive plate 452 and the second conductor plate 654 with a root 142(e.g., between d_(r)) provides an alternate path through root impedance418, which is an effective impedance characterized by the alternate pathfor the electrons to flow from the second conductor plate 654 to thepolarized root 142 and then from the polarized root 142 to the firstconductor plate 452. Consequently, the overall impedance of the soilbetween the first conductor plate 452 and the second conductor plate 654becomes the capacitance of the soil C_(soil) in parallel with theoverall capacitance of the root C_(root) in parallel with the resistanceof the soil R_(soil) in parallel with the overall resistance of the rootR_(root,) as depicted in FIG. 8B. In some examples, the overallimpedance decreases between the first conductive plate 452 and thesecond conductor plate 654.

It should be appreciated that earth ground and chassis ground can havedifferent voltage potentials (e.g., V_(Earth)≠V_(chassis)). That is,even for instances where an electrical wire shorts the chassis ground toearth ground the electrical wire connection has a non-zero lineimpedance 422. In some instances of poor grounding, the electrode 138can be positioned on the chassis ground rather than the earth grounddepicted in FIG. 8A.

It should also be appreciated that the capacitance of the soil C_(soil),the overall capacitance of the root C_(root), the resistance of the soilR_(soil) and the overall resistance of the root R_(root), can vary basedon the resistivity, salinity, moisture content, temperature, aeration,aggregation (e.g., rocky, clay, sand), and the like. Likewise, thevalues for the capacitance of the soil C_(soil) in parallel with theresistance of the soil R_(soil) between the configuration depicted inFIG. 7A can be different from the values for the capacitance of the soilC_(soil) in parallel with the resistance of the soil R_(soil) in theconfiguration depicted in FIG. 8A.

Because the charge is no longer confined to the first conductor plate452 for dissipation through the soil (e.g., soil impedance), the firstconductor plate 452 has a characteristic signal response profile that isdistinct from a baseline signal response, which is similar to theresponse of FIGS. 7A and 7B. In the instance of FIGS. 8A and 8B, thesignal processor 410 compares the conditioned signal to the baselinesignal and the determinator 414 determines that a root 142 is detectedbetween the first conductor plate 452 and the second conductor plate 654because the conditioned response signal is distinct from the baselinesignal response (e.g., signal response without a root present). In someexamples, determinator 414 is a digital comparator configured todetermine whether the difference between portions of the conditionedsignal response and portions of the baseline signal response exceeds athreshold value. For instance, the determinator 414 can determine that aroot is detected when a peak of the response signal exceeds a thresholdvalue (e.g., 90% of peak from baseline signal). In another instance, thedeterminator 414 can determine that a root is detected when a peak ofthe response signal drops below a threshold value (e.g., 90% of peakfrom baseline signal).

FIGS. 9A and 9B are circuit diagrams illustrating an example of a rootproximity sensor configured to determine whether a root is between afirst conductive plate 452 and a second conductor plate 654 at instanceswhen a root impinges on at least one conductor plate. The proximitysensor 700 has the same components as described in FIGS. 7A, 7B, 8A, and8B above. As depicted in FIG. 9A, the root 142 is in contact with thefirst conductor plate 452. As such, the charge on the first conductorplate 452 is distributed throughout root 142. The distribution of chargeprovides an additional electrical path (e.g., root impedance 418) fordissipation. In this example, the charge is no longer confined to thefirst conductor plate 452 for dissipation through the soil (e.g., soilimpedance 416 path). Instead, the charge is distributed along the root142 (e.g., root impedance 416 path), which changes the characteristicsignal response profile from the baseline signal response.

Consequently, the overall impedance of the soil between the firstconductor plate 452 and the second conductor plate 654 becomes thecapacitance of the soil C_(soil) in parallel with the overallcapacitance of the root C_(root) in parallel with the resistance of thesoil R_(soil) in parallel with the overall resistance of the rootR_(root), as depicted in FIG. 8B. In some examples, the overallimpedance decreases between the first conductive plate 452 and thesecond conductor plate 654. It should be appreciated that thecapacitance of the soil C_(soil), the overall capacitance of the rootC_(root), the resistance of the soil R_(soil), and the overallresistance of the root R_(root) can vary based on the resistivity,salinity, moisture content, temperature, aeration, aggregation (e.g.,rocky, clay, sand), and the like. Likewise, the values for the C_(soil)in parallel with the overall capacitance of the root C_(root) inparallel with the resistance of the soil R_(soil) in parallel with theoverall resistance of the root R_(root) between the configurationdepicted in FIG. 8A can be different from the values of the C_(soil) inparallel with the overall capacitance of the root C_(root) in parallelwith the resistance of the soil R_(soil) in parallel with the overallresistance of the root R_(root) for the configuration depicted in FIG.9.

It should he appreciated that earth ground and chassis ground can havedifferent voltage potentials (e.g., V_(Earth)≠V_(chassis)). That is,even for instances where an electrical wire shorts the chassis ground toearth ground, the electrical wire connection has a non-zero lineimpedance 422. In some instances of poor grounding, the electrode 138can be positioned on the chassis ground rather than the earth grounddepicted in FIGS. 9A and 9B.

As depicted in FIGS. 7A, 7B, 8A, and 8B, the root proximity sensor 700can optionally include a polarity switch 706 electrically coupled toswitch 406, the first conductor 452 and the second conductor 654. Thepolarity switch is configured to provide a second configuration thatexchanges electrical coupling between the first conductor plate 452 andthe second conductor plate 654. That is, the polarity switch 706reconfigures the electrical coupling such that the first conductor plate452 is electrically coupled to ground (e.g., chassis ground) and thesecond conductor plate 654 is electrically connected to the power supply402 in the first mode or the signal extractor 404 through the switch 406in the second mode.

FIG. 9B depicts an instance with the polarity switch 706 thrown suchthat the first conductor plate 452 is electrically coupled to ground(e.g., chassis ground) and the second conductor plate 654 iselectrically coupled to the power supply 402 in the first mode of theswitch 406 while the root 142 is in contact with the first conductorplate 452. In such an instance, the electrons from the first conductorplate 452 are distributed throughout root 142 causing the root to begrounded (or close to being grounded). It has been found that thedistribution of the electrons along root 142 further assists ingrounding and weakly affects additional electrical distribution paths(e.g., root impedance 418). The reason is attributed to the positivecharge being confined to the second conductor plate 654 for dissipationthrough the soil (e.g., soil impedance 416 path), which is substantiallysimilar to the characteristic signal response profile from the baselinesignal response (e.g., signal response without the root 142).

The difference in signal profile from the configuration of FIG. 9Acompared to the configuration of FIG. 9B is that it provides a symmetrymetric. That is, a root 142 in contact with the first conductor plate452, as depicted in FIG. 9A, provides a signal profile characteristic ofa root's presence. The polarity switch 706 configured as depicted inFIG. 9B does not provide a signal profile characteristic of a root'spresence. Likewise, a root 142 in contact with the second conductorplate 654 provides a signal profile characteristic of a root's presencewhen the polarity switch 706 is configured such that the first conductorplate 452 is electrically coupled to ground (e.g., chassis ground) andthe second conductor plate 654 is electrically connected to the powersupply 402 in the first mode or the signal extractor 404 through theswitch 406 in the second mode. Whereas the polarity switch 706 isconfigured such that the second conductor plate 654 is electricallycoupled to ground (e.g., chassis ground) and the first conductor plate452 is electrically connected to the power supply 402 in the first modeof the switch 406 in the second mode, which does not substantiallyprovide a signal profile characteristic of a root's presence.

FIGS. 10A-10C are diagrams illustrating an example of a non-invasiveroot phenotyping device 600 with a plurality of parallel conductorplates 626 surrounding a plant at various stages of growth of a plantroot system over time 1000A, 1000B, 1000C. As depicted in FIGS. 10A-10C,the root phenotyping device 600 includes a plurality of parallelconductor plates 626 affixed to a portion of sensor array 625, which areextended around the circular supports 122A, 122B, 122C to enclose acylindrical surface around the plant 140. The portion of sensor array625 is trellised to cage structure 120 and is similar to the rootphenotyping device 600 depicted in FIG. 6. Although a single portion ofsensor array 625 is depicted, portions of sensor array 625 are intendedto be disposed in each space between vertical supports and circularsupports 122A, 122B, 122C.

At time 1000A, seed 540 is planted in a soil at a specified location ata known depth. The root phenotyping device 600 is buried around thissoil location such that the location of seed 540 is at or near anapproximate center of cage structure 120. In some examples, the rootphenotyping device 600 can be buried prior to time 1000A depicted inFIG. 10A. For example, multiple root phenotyping devices 600 can beinstalled along a row, at an instance in time, and individual seeds 540can be planted at or near the center of each root phenotyping device 600at a later instance in time using an automated planter. In someinstances, root phenotyping device 600 can be buried after seed 540 hasbeen planted without interfering with the roots 142. For example, rootphenotyping device 600 can be buried while plant 140 is at a stage ingrowth similar to that depicted in FIG. 5B.

FIG. 10B represents a later time than FIG. 10A, where the seed 540 hassprouted and has grown into a small plant with relatively small roots142 that emanate from the known planted location. In this instance, theroots 142 emanate from the plant 140 at or near the origin of where theseed 540 had been planted in FIG. 10A. As depicted in FIG. 10B, the rootphenotyping device 600 does not detect a root 142 presence because theroots do not touch either the first conductor plate 452 or the secondconductor plate 654 of the proximity sensor 700. Likewise, the roots 142have not grown between the first conductor plate 452 and the secondconductor plate 654 of the proximity sensors.

FIG. 10C represents a later time than FIG. 10B, where the plant 140 andthe roots 142 have grown. In this instance, the roots 142 have grownsufficiently to touch either the first conductor plate 452 or the secondconductor plate 654 of the proximity sensors of at least a portion ofsensor array 625. Likewise, the roots 142 have grown sufficiently to bedisposed between the first conductor plate 452 and the second conductorplate 654 of the parallel conductor plates 626 or at least a portion ofsensor array 625. In such an instance, the parallel conductor plate626A1 has a root 142 touching the second contact plate 654. Also, theparallel conductor plate 626A1 has a root 142 between the firstconductor plate 452 and the second conductor plate 654. Consequently,the extracted signal response is conditioned (e.g., via signal processor412) and compared to a baseline signal response (e.g., via determinator414) and determined by the microcontroller 410 that a root 142 is inproximity with parallel conductor plate 626A1 and parallel conductorplate 626A5 at a designated time (e.g., timestamp).

In some instances, the parallel conductor plates 626 of proximity sensor700 do not detect a root 142 below the parallel conductor plates 626A1-X(e.g., no root at parallel conductor plates 626B1-X, 626C1-X, etc.). Insuch an instance, the root phenotyping devices 600 can determine theroot approximate growth rate (e.g., distance to parallel conductorplates 626A1, 626A5 divided by the time of initial detection) as well asthe approximate depth of the root system.

FIG. 11 is a diagram illustrating an ISO view of a non-invasive rootphenotyping device 1100 with a proximity sensor array 625 and aplurality of proximity sensors trellised on a stake 1120. The stake 1120is a support structure suitable for arrangement in a soil locationadjacent to plant 140. In this example, the support structure is aplanar structure with a lateral support 1122 vertically connectedbetween vertical supports 1110, which forms a backbone for the supportstructure. In some examples, the support structure is made from anymaterial that resists deformation upon insertion into a desired soiltype without affecting the health and growth of the plant 140. Forexample, the material of the support structure of a stake 1120 can be ametal (e.g., galvanized steel, stainless steel), a plastic (e.g.,bioplastics), and the like. In some examples, the material of thesupport structure of a stake 1120 is made from biodegradable and/orcompostable material such as polylactic acid (PLA),poly-3-hydroxybutyrate (PHB), polyhydroxyalkanoates (PHA), and the like.In some instances, a 3-D printer can be utilized to construct thesupport structure of a stake 1120 using a suitable thermoplastic (e.g.,PLA, etc.). In some instances, the support structure of a stake 1120 canbe injected molded using a suitable thermoplastic (e.g., PLA, etc.)

The root phenotyping device 1100 further includes a plurality ofparallel conductor plates 626 and/or conductor plates 126 affixed to thesupport structure (e.g., support structure of stake 1120). For example,the plurality of sensors is a plurality of parallel conductor plates 626that are trellised between the adjacent lateral supports 1122. In someexamples, the plurality of sensors is a plurality of conductor plates126 affixed to the lateral support 1122. In some examples, the pluralityof sensors is a plurality of conductor plates 126 affixed to thevertical supports 1110. In some examples, the plurality of sensors is aplurality of parallel conductor plates 626 with the first conductorplate 452 and the second conductor plate 654 affixed to the verticalsupports 1110 and/or the lateral supports 1222. The extended verticalsupports 1110 provide for a relatively fixed position during insertioninto a soil location and subsequent operation. In some instances, one ormore of the plurality of conductor plates 126 can be provided on a meshthat is positioned between the vertical supports 1110 and the lateralsupports 1222.

As depicted in FIG. 11 the stake 1120 is tilted at an angle θ₂ withrespect to the base of the root 142. In some examples, the conductorplates 126 are oriented substantially parallel to the base of a root142. In some examples, the conductor plates 126 are tilted at obliqueangles with respect to the base of a root 142. That is, the conductorplates 126 are situated at a slant from the +y direction (e.g., y axis)toward the +z direction (e.g., z axis) with respect to a lateral (x-yplane) base of the root 142.

Each of the plurality of conductor plates 126 is electrically coupled(e.g., via wired interconnects) to a controller 130 (e.g.,microcontroller) that is configured to determine whether a root ispresent in proximity to a conductor plate 126. As depicted in FIG. 11,controller 130 includes a communications unit (e.g., antenna 108, I/Oport for cable 106) configured to transmit sensory data to a mobiledevice 154 (e.g., smart phone, tablet PC). In some instances, thecommunications unit can transmit sensory data over cable 106 to a mobiledevice 154. In some instances, cable 106 is a serial cable withappropriate connectors to interface with the communication unit ofcontroller 130 and the mobile device 154. In such an instance, thecommunication unit includes circuitry (e.g., serial transceiver, etc.)to transmit and receive serial communications. In some examples, thecommunications unit can include an antenna 108 and circuitry configuredto transmit sensory data wirelessly (e.g., Bluetooth, WiFi) to mobiledevice 154. In such an instance, the communication unit includescircuitry (e.g., Bluetooth transceiver, WiFi transceiver, etc.) totransmit and receive communications via wireless protocols. In someexamples, the communications unit can include an antenna 108 andcircuitry configured to transmit sensory data over a cellular network(e.g., 3G, 4G, LTE) to cellular tower or mobile device 154. In such aninstance, the communication unit includes circuitry (e.g., 3Gtransceiver, 4G transceiver, LTE transceiver, etc.) to transmit andreceive communications via cellular protocols.

It should be appreciated that the root phenotyping device 1100 can alsoinclude one or more sensors (e.g., soil sensor 134, ambient sensor 136)associated with any desired aspect of plant 140, the soil location,and/or one or more above-ground conditions at or near the soil location.Similarly, it should be appreciated that the root phenotyping device1100 can include additional stakes 1120 to surround the plant 140. Insome examples, the stakes include interlocking mechanisms that guidepositioning of adjacent stakes 1120. In some examples, the stakes form acage structure that surrounds the plant 140.

FIG. 12 is a conceptual data flow diagram illustrating the data flowbetween different means/components at a root phenotyping device 1200.The root phenotyping device 1200 is for monitoring growth of a root of aplant in a soil location and can be the root phenotyping device 100depicted in FIG. 1, the root phenotyping device 600 depicted in FIG. 6,or the root phenotyping device 1100 depicted in FIG. 11.

As depicted in FIG. 12, the controller 130 of the root phenotypingdevice 1200 includes a power supply 402, signal extractor 404,microcontroller 410, computer readable medium/memory 408, acommunication unit 1240, and an I/O connector 1250. Microcontroller 410further includes a signal processor 412, a determinator 414, and atimer/clock 1220.

The communication unit 1240 includes a wireless unit 1242A and a wiredunit 1242B. The wireless unit 1242A has a transmitter 1246A and receiver1244A configured to transmit sensory data to a mobile device 154 (e.g.,smart phone, tablet PC). The communications unit 1240 can include anantenna 108 that, along with the transmitter 1246A and receiver 1244A,can transmit sensory data wirelessly (e.g., Bluetooth, WiFi) to mobiledevice 154. In some examples, the transmitter 1246A and the receiver1244A transmit and receive communications via wireless protocols. Insome examples, the transmitter 1246A and the receiver 1244A transmit andreceive communications via cellular protocols over a cellular network(e.g., 3G, 4G, LTE). The wired unit 1242B has a transmitter 1246B and areceiver 1244B configured to transmit sensory data over cable 106 to amobile device 154. In some examples, the cable 106 is a serial cablewith appropriate connectors to interface with the I/O connector 1250 andthe mobile device 154. In some examples, the transmitter 1246B and thereceiver 1244B can transmit and receive serial communications.

The computer-readable medium/memory 408 can store one or more baselinesignal responses 1232 (e.g., 1^(st) signal through m^(th) signal) thatare applicable to conditions in the soil. For example, one baselinesignal response 1232 (e.g., 1^(st) signal) can be a signal response forwet, salty soils where the impedance can be low (e.g., resistivity ˜10Ω-m). Another baseline signal response 1234 (e.g., 2^(nd) signal) can bea signal response for dry soils where the impedance can be high (e.g.,resistivity ˜1 kΩ-m). Another baseline signal response 1232 (e.g.,1^(st) signal) can be a signal response for very dry soils where theimpedance can be even higher (e.g., resistivity ranging between 1 kΩ-mto 10 kΩ-m).

The computer-readable medium/memory 408 can store also one or moresignal responses 1234 (e.g., 1^(st) signal through n^(th) signal) thatare applicable to conditions in the soil. For example, one signalresponse 1234 (e.g., 1^(st) signal) can be a signal response for wetsalty soils where the impedance can be low (e.g., resistivity ˜10 Ω-m).Another signal response 1234 (e.g., 2^(nd) signal) can be a signalresponse for dry soils where the impedance can be high (e.g.,resistivity ˜1 kΩ-m). Another signal response 1234 (e.g., 1^(st) signal)can be a signal response for very dry soils where the impedance can beeven higher (e.g., resistivity ranging between 1 kΩ-m to 10 kΩ-m).

In one configuration, the root phenotyping device 1200 includes anelectronic sensor for detecting a root of a plant 140 in soil. Theelectronic sensor is a contact sensor 400 (of FIG. 4) that includes afirst conductor plate 452 configured to be disposed in soil, a switch406, a signal extractor 404, and a power supply 402. The switch 406 isconfigured to switch between a first mode and a second mode. The powersupply 402 is electrically coupled to the switch 406 and the powersupply 402 is configured to provide an electrical charge to the firstconductor plate 452 in the first mode of the switch 406. The signalextractor 404 is electrically coupled to the switch 406 and the signalextractor 404 is configured to capture a signal response 1234 at thefirst conductor plate 452 in the second mode of the switch 406. In someexamples, the signal extractor 404 is a voltage divider. In someexamples, the signal extractor 404 is an analog to digital converter.

The electronic sensor further includes a microcontroller 410electrically coupled to the signal extractor 404 and a computer readablemedium/memory 408 electrically coupled to the microcontroller 410. Asdepicted in FIG. 12, the microcontroller 410 further includes a signalprocessor 412, a determinator 414, and a timer/clock 1220. The memory isconfigured to store data associated with the signal extractor 404. Thesignal processor 412 of the microcontroller 410 is configured to receivethe signal response 1234 from the signal extractor 410. In someexamples, the signal processor 412 of the microcontroller 410 isconfigured to retrieve a baseline signal response 1232 from computerreadable medium/memory 408.

In some examples, the determinator 414 of the microcontroller 410 isconfigured compare the signal response to the baseline signal response1232 to determine whether a difference between a portion of the signalresponse and a portion of the baseline signal 1232 response exceeded athreshold value. In such an instance, the presence of a root 142 isassociated with a determination that the signal response 1232 exceededthe threshold value.

In another configuration, the electronic sensor is a proximity sensor700 (of FIG. 7) that further includes a second conductor plate 654configured to be disposed in soil adjacent to and substantially parallelto the first conductor plate 452. The second conductor plate 654 iselectrically coupled to ground (e.g., earth ground and chassis ground).In some examples, a gap between the first conductor plate 452 and thesecond conductor plate 654 has a cross sectional area of less than orequal to about 1 cm². In some configurations, a distance between thefirst conductor plate 452 and the second conductor plate 654 is equal toor greater than about 1 mm. In some examples, the electronic sensorfurther includes a polarity switch 706 configure to exchange electricalcoupling between the first conductor plate 452 and the second conductorplate 654.

In some examples, the switch 406 is a multiplexer that is electricallycoupled to and controlled by the microcontroller 410. In some examples,the switch 406 is a relay that is electrically coupled to and controlledby the microcontroller 410. In some examples, the electronic sensorfurther includes a soil humidity sensor (e.g., soil sensor 134) or atemperature sensor (e.g., ambient sensor 136) electrically coupled tothe microcontroller 410. In some examples, the electronic sensor isoriented at an oblique angle with respect to a lateral of a root base.In some examples, the electronic sensor is affixed to a mesh suspendedbetween members of support structure (e.g., vertical supports 110 andcircular supports 122A, 122B, 122C). In some examples, the baselinesignal response 1232 is representative of a signal response 1234 of theelectronic sensor in soil without a root 142 disposed between the firstconductor plate 452 and the second conductor plate 654 or without a root142 that is in contact with either the first conductor plate 452 or thesecond conductor plate 654. In some examples, the signal response 1234is stored in the computer readable medium/memory 408 at predetermined(e.g., periodic) intervals.

In another configuration, the root phenotyping device 1200 is anelectronic device for monitoring growth of a root of a plant 140 in asoil location. The electronic device includes a support structure (e.g.,cage structure 120, stake 1120, auger) suitable for arrangement adjacentto the soil location. The electronic device further includes a pluralityof electronic sensors affixed to the support structure.

At least one of the plurality of sensors is a contact sensor 400 thatincludes a first conductor plate 452, a switch 406, a signal extractor404, and a power supply 402. The switch 406 is configured to switchbetween a first mode and a second mode. The power supply 402 iselectrically coupled to the switch 406 and the power supply 402 isconfigured to provide an electrical charge to the first conductor plate452 in the first mode of the switch 406. The signal extractor 404 iselectrically coupled to the switch 406 and the signal extractor 404 isconfigured to capture a signal response 1234 at the first conductorplate 452 in the second mode of the switch 406. In some examples, thesignal extractor 404 is a voltage divider. In some examples, the signalextractor 404 is an analog to digital converter.

The electronic device further includes a microcontroller 410electrically coupled to the signal extractor 404 and a computer readablemedium/memory 408 electrically coupled to the microcontroller 410. Asdepicted in FIG. 12, the microcontroller 410 further includes a signalprocessor 412, a determinator 414, and a timer/clock 1220. The memory isconfigured to store data associated with the signal extractor 404. Thesignal processor 412 of the microcontroller 410 is configured to receivethe signal response 1234 from the signal extractor 410. In someconfigurations, the signal processor 412 of the microcontroller 410 isconfigured to retrieve a baseline signal response 1232 from computerreadable medium/memory 408.

In some examples, the determinator 414 of the microcontroller 410 isconfigured to compare the signal response to the baseline signalresponse 1232 to determine whether a difference between a portion of thesignal response and a portion of the baseline signal 1232 responseexceeded a threshold value. In such an instance, the presence of a root142 is associated with a determination that the signal response 1232exceeded the threshold value.

In some examples, at least one of the plurality of sensors is aproximity sensor 700 that further includes a second conductor plate 654adjacent to and substantially parallel to the first conductor plate 452.The second conductor plate 654 is electrically coupled to ground (e.g.,earth ground and chassis ground). In some examples, a gap between thefirst conductor plate 452 and the second conductor plate 654 has a crosssectional area of less than or equal to about 1 cm². In someconfigurations, a distance between the first conductor plate 452 and thesecond conductor plate 654 is equal to or greater than about 1 mm. Insome examples, the electronic device further includes a polarity switch706 configured to exchange electrical coupling between the firstconductor plate 452 and the second conductor plate 654.

In some examples, the switch 406 is a multiplexer that is electricallycoupled to and controlled by the microcontroller 410. In some examples,the switch 406 is a relay that is electrically coupled to and controlledby the microcontroller 410. In some examples, the electronic devicefurther includes a soil humidity sensor (e.g., soil sensor 134) or atemperature sensor (e.g., ambient sensor 136) electrically coupled tothe microcontroller 410. In some examples, at least one of the pluralityof sensors is oriented at an oblique angle with respect to a lateral ofa root base. In some examples, at least one of the plurality of sensorsis affixed to a mesh suspended between members of the support structure(e.g., vertical supports 110 and circular supports 122A, 122B, 122C). Insome examples, the baseline signal response 1232 is representative of asignal response 1234 of the electronic sensor in soil without a root 142disposed between the first conductor plate 452 and the second conductorplate 654 or without a root 142 that is in contact with either the firstconductor plate 452 or the second conductor plate 654. In some examples,the signal response 1234 is stored in the computer readablemedium/memory 408 at predetermined (e.g., periodic) intervals.

FIG. 13 is a flow diagram 1300 of a plant phenotyping device with aplurality of sensors to detect roots 142 and determine root traits. Theplant phenotyping device can be the non-invasive root phenotyping device100, non-invasive root phenotyping device 600, or non-invasive rootphenotyping device 100. The root phenotyping device is configured todetect and to monitor a root presence at a conductor plate 126 and storethe location in computer readable medium/memory 408 along with othercharacteristic data (e.g., temperature, soil resistivity, soil humidity,ambient humidity, ambient temperature, timestamp, etc.).

At block 1302 the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) electrically charges a firstconductor plate 452 from a power supply 402 over a first predeterminedtime and determines whether the charging is complete. For example, theswitch 406 can be thrown to a first mode in which the power supply 402is electrically coupled to provide an electrical charge to the firstconductor plate 452, as depicted in FIG. 4A and FIG. 7A. In someinstances, the first predetermined time exceeds a time constantassociated with soil impedance 416 between the first conductor plate 452and an earth ground electrode 138. In some instances, the predeterminedtime can be an adjustable configuration to the plant phenotype device.

At block 1304 the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) electrically uncouples thefirst conductor plate 452 from the power supply 402. For example, theswitch 406 can be thrown to a second mode in which the signal extractor404 is enabled to capture the signal response 1234. That is, the powersupply 402 is electrically uncoupled from the first conductor plate 452and the signal extractor 404 is electrically coupled to the firstconductor plate 452.

At block 1306 the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) electrically grounds a secondconductor plate 654. The second conductor plate 654 is adjacent to andsubstantially parallel to the first conductor plate 452. It should berecognized that this is optional for contact sensors 400 and particularto proximity sensor 700. For proximity sensors 700, which includes asecond conductor plate 654 the second conductor plate 654 is grounded tochassis ground prior to extracting measurements. The grounded secondconductor plate 654 provides a reference ground plane for the firstconductor plate 452 to facilitate signal response profiles.

At block 1308 the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) extracts a signal response 1234at the first conductor plate 452 over a second predetermined time. Thatis, the charge applied to the first conductor plate 452 dissipates overtime as electrons flow from the earth ground of the electrode 138through the soil to the first conductor plate 452. While the firstconductor plate 452 is discharging signal extractor 404 can extractcharge or voltage levels. This yields a signal response 1234proportional to electrical properties of the soil (e.g., soil impedance416). In some examples, the signal extractor is a voltage divider, wherethe extracted voltage is a ratio of impedances (e.g.,v₀=Z₁/(Z₁+Z₂)×v_(in)).

In some examples, signal extractor 404 is an ADC configured to convertthe signal response to digital equivalents. In such an example, the ADCcan be configured to digitally capture the signal response. It should beappreciated that the extracted signal (e.g., voltage) from the ADC iswith respect to the chassis ground of controller 130, which is common toa plurality of conductor plates 126. In some examples, the secondpredetermined time exceeds a time constant associated with soilimpedance 416 between the first conductor plate 452 and an earth groundelectrode 138. In some examples, the second predetermined time isadjustable.

In addition, signal processor 412 can condition the response signal 1234so that it is more suitable for comparison. For example, the responsesignal 1234 can have high-frequency noise, and the signal processor 412can apply a low-pass filter (e.g., Butterworth filter, Chebyshev filter,Cauer filter, etc.) to condition the signal response 1234.

At block 1310, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) retrieves the baseline signalresponse 1232 from computer readable medium/memory 408. For example, thesignal processor 412 can retrieve from the computer readablemedium/memory 408 (e.g., query a database), a baseline response signal1232 for a soil that has similar resistivity and temperature to comparewith the conditioned signal response. It should be appreciated thatadditional soil characteristics can also be applied when determining abaseline response signal such as salinity, aeration, etc.

At block 1312, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) determines whether a portion ofthe signal response 1234 exceeds a threshold value. A root presence isassociated with a determination that the portion of the signal response1234 exceeded the threshold value. For example, the plant phenotypingdevice can include a microcontroller 410 with a determinator 414 thatcompares the signal response 1234 to the baseline signal response 1232to determine whether a root 142 is present.

In some examples, determinator 414 is a digital comparator configured todetermine whether the difference between portions of the (conditioned)signal response 1234 and portions of the baseline signal response 1232exceeds a threshold value. In one instance, a portion of the baselinesignal response 1232 can be a peak (e.g., max or relative max value)that corresponds to a peak (e.g., max or relative max value) of thesignal response 1234. In such an instance, the determinator 414 candetermine that no root 142 is detected for a peak of the signal response1234 exceeding a threshold value (e.g., 90% of peak from baselinesignal).

At block 1314, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) determines the biomass inaccordance with the signal response 1234 exceeding a threshold value(e.g., root detected). The biomass is proportional to a capacitancemagnitude of the signal response 1234. In some examples, the biomassgrowth rate is proportional to the change in biomass over an elapsedtime.

In some examples, each detected root 142, among the plurality ofsensors, can be spatially mapped (e.g., to form a biomass map). In someexamples, before the sensory data is mapped to biomass, it ispreprocessed to identify errant data or missing data, perhaps caused bydevice malfunction or environmental conditions. In such examples, theaccuracy is improved as some biomass data may not correspond to rootbiomass due to measurement error.

In some examples, a dynamic linear model with heteroskedastic errors isused to infer the latent (unobserved) root biomass evolution. In someinstances, the latent root biomass is stored as a three dimensionalarray indexed by observation number, level, and level offset (e.g.,designated 626A1-626A5, 626B1-626B5, 626C1-626C5 etc. positions) In someinstances, residual heteroskedasticity is used to search for transientprocesses, like soil organisms such as worms or insects coming incontact with the device. Very large residuals indicate the presence ofsuch soil organisms. In some instances, the underlying parameters of themodel are adapted through standard statistical techniques.

At block 1316, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) determines the growth rate inaccordance with the signal response 1234 exceeding a threshold value(e.g., root detected). The root growth rate is proportional to athree-dimensional coordinate of the conductor plate 126 over an elapsedtime. For example, a timestamp of a positive detection can be comparedagainst a timestamp of the seed 540 planting, or other referencetimestamp, to determine a growth duration, which is then used to factorgrowth rate in conjunction with the root length determination.

Other growth rates are contemplated and can be extrapolated from data.For example, a local rate of growth can he determined by the incrementalincrease of biomass of each newly positive detected root 142. Likewise,a global rate of growth can be determined by the rate at which the root142 are coming into contact with sensors at each different level (e.g.,corresponding to different root lengths). As such, properties ofindividual roots and global RSA properties can be calculated.

As part of the growth rate, the root length can also be calculated. Forexample, a three-dimensional coordinate of the sensor (e.g., conductorplate 126 or parallel conductor plate 626) can provide an approximateroot length from the coordinate of the seed 540 location. This providesan inference of global RSA growth based on knowledge about theproportion of roots that are likely to come in contact with a sensor(e.g., conductor plate 126 or parallel conductor plate 626).

At block 1318, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) determines the root angle inaccordance with the signal response 1234 exceeding a threshold value(e.g., root detected). The root angle is based on an angle between apoint of origin (e.g., origin of the seed) or a crown of the plant root142 and a three-dimensional coordinate of the sensor (e.g., conductorplate 126 or parallel conductor plate 626).

In some examples, the root angle is determined by calculating the anglebetween the three-dimensional coordinate of the respective sensor (e.g.,conductor plate 126 or parallel conductor plate 626) and the location inwhich the seed 540 was planted (or the location from which the plantroot system emanates). The root phenotyping device 100, 600 of thepresent disclosure can dictate the soil location at which the seed 540is planted. Hence, the point of origin (e.g., origin of the seed) of theroot emanation location is calculated as a predetermined distance abovethe seed 540. The root emanation location, the radius of each level, andthe depth of each level, can be used to calculate the amount of rootbiomass growing at certain altitude angles relative to the rootemanation location.

In some instances, the root growth is not circularly symmetric (e.g.,elliptical or oblong-shaped). The root emanation location and the sensor(e.g., conductor plates 126 or parallel conductor plates 626) locationscan be used to record root growth at certain azimuth angles. In someinstances, the sensor (e.g., conductor plate 126 or parallel conductorplate 626) locations summarize root growth in terms of the primary andsecondary directions of variation perpendicular to the surface normal.In some examples, the total root biomass at each point in time can beconverted to proportions of the root system growing at the each altitudeangle over time.

Aspects of RSA, such as root angle (e.g., point of origin root angle),contribute to plant growth and nutrient acquisition. The correlation ofthe root angle to plant growth is particularly relevant to resourceresistance. For example, steep-angled roots provide row to row cropssuch as maize access to ground water during droughts, whereas shallowerroots increase the uptake of immobile nutrients found in shallow soils,such as phosphorus.

At block 1320, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) stores a root presenceindicator to the computer readable medium/memory 408 in accordance withthe portion of the signal response 1234 exceeding the threshold value.In some examples, additional information (e.g., soil resistivity,temperature, timestamp, signal response, coordinate location, etc.) arcstored with the root presence indicator. In some examples, the rootpresence indicator is stored in a database.

At block 1322, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) determines whether thepredetermined sample time has elapsed. In some examples, the sample timeis the number of days for a particular crop season. In some examples,the root phenotyping device can be enabled to gather data indefinitely(e.g., gather data until user intervenes).

At block 1324, the plant phenotyping device (e.g., non-invasive rootphenotyping device 100, 600, 1100, etc.) transmits data for postprocessing in accordance with the predetermined sample time thatelapsed. In some examples, a cable 106 can be used to connect a mobiledevice 154 to the controller 130 (e.g., I/O connector 1250) and the data(e.g., root presence indicator, soil resistivity, temperature,timestamp, signal response, coordinate location, etc.) can betransmitted to the mobile device 154 for further processing. In someexamples, that mobile device 154 can interface with the controller 130wirelessly (e.g., Bluetooth, WiFi, etc.) and the data (e.g., rootpresence indicator, soil resistivity, temperature, timestamp, signalresponse, coordinate location, etc.) can be transmitted wirelessly tothe mobile device 154 for further processing.

In some examples, the techniques of the present disclosure implementmultiple non-invasive root phenotyping devices 100, 600, 1100. Forexample, as depicted in FIG. 11, the non-invasive root phenotypingdevice 1100 implements a two stakes 1120. The techniques can alsoimplement two or more non-invasive root phenotyping device 100, 600,1100 having different sizes around a single soil location. Thisfacilitates the capture of additional root interactions over time, ascompared to the use of a single device.

It should be appreciated that the techniques described above formonitoring growth of plant root(s) can be adapted for a variety of uses.The steps of positioning a plurality of sensors (e.g., conductor plate126 or parallel conductor plate 626) around a soil location, planting aseed 540 in the soil location, receiving data representing a rootpresence, and determining a root growth characteristic of a plant rootbased on the data, as well as the optional features and elements, canfind use, alone or in combination, with any of the techniques describedherein.

Certain aspects of the present disclosure relate to techniques forselecting a plant for breeding based on a root growth characteristic. Insome examples, the techniques include positioning a plurality ofconductor plate 126 (e.g., for conductor plate 126 or parallel conductorplate 626) around a soil location, planting a seed 540 in the soillocation, receiving data representing a root presence from a plant root142 after the seed 540 has grown into a plant 140, determining a rootgrowth characteristic of the plant root based on the data, and selectingthe plant for breeding based on the determined root growthcharacteristic.

A variety of root growth characteristics, including, growth rate, rootangle, root length, and root biomass, can be desirable characteristicsfor selection and breeding. In some examples, different root angles areadvantageous for acquisition of different soil resources. For example,if a breeder wishes to maximize shallow resource uptake (e.g.,phosphorus), the breeder to can select plants with shallower root anglesLikewise, if a breeder wishes to maximize deep resource uptake (e.g.,nitrogen or water during drought conditions), the breeder can selectplants 140 with deeper root angles. The techniques of non-invasive rootphenotyping described herein allow for the real-time determination of amultitude of root growth characteristics, which enables large-scalescreening and identification of plants or cultivars with desired or newroot growth characteristics. This facilitates new hybrid cultivars asthese cultivars can be tested against a commercial variety to determinewhether the cultivars have different root growth characteristic.

In some examples, the techniques further include crossing the plantdetermined to have a particular root growth characteristic with a secondplant of the same species to produce a progeny plant. In some examples,the second plant has the same root growth characteristic, therebyallowing the fixation of a characteristic of interest. In otherexamples, the second plant has a different desired root growthcharacteristic, thereby crossing multiple characteristics to achieve newand/or desirable permutations of RSA properties.

A number of selection and breeding techniques can be suitably used inthe techniques of the present disclosure including, recurrent selection,mass selection, bulk selection, backcrossing, pedigree selection,modified pedigree selection, selfing, sibbing, hybrid production,crosses to populations, open pollination breeding, restriction fragmentlength polymorphism enhanced selection, genetic marker enhancedselection, making double haploids, and transformation, and the like. Itshould be appreciated that each technique can be implements alone or incombination with other techniques.

In some examples, the devices, techniques, and/or computer-readablestorage media of the present disclosure can be used in the production ofhybrid plant varieties. For example, varieties can be produced tointroduce the traits or characteristics (e.g., one or more root growthcharacteristics of the present disclosure) of a variety into otherlines, or provide a source of breeding material that can be used todevelop new inbred varieties. The development of hybrids in a plantbreeding program requires, in general, the development of homozygousinbred varieties, the crossing of these varieties, and the evaluation ofthe crosses. There are many analytical techniques to evaluate the resultof a cross. Some techniques include the observation analysis ofphenotypic traits, while other techniques include genotypic analysis.

In some examples, backcross breeding is implemented to transfer one or afew favorable genes for a highly heritable trait (e.g., a root growthcharacteristic of the present disclosure) into a desirable variety. Thisapproach can be used for breeding disease-resistant varieties. Variousrecurrent selection techniques can be used to improve quantitativelyinherited traits controlled by numerous genes. The use of recurrentselection in self-pollinating crops depends on the ease of pollination,the frequency of successfully pollinated hybrids, and the number ofhybrid offspring from each successful cross. Promising advanced breedinglines can be thoroughly tested and compared to appropriate standards inenvironments representative of the commercial target area(s) for adesignated period of time. The best lines can then be candidates for newcommercial varieties. Those still deficient in a few traits can befurther used as parents to produce new populations for additionalselection.

In some examples, a breeding scheme includes crosses and/or selfing. Forinstance, a breeder can initially select and cross two or more parentallines, followed by repeated selfing and selection, to produce many newgenetic combinations. Moreover, a breeder can generate multipledifferent genetic combinations by crossing, selfing, and mutations. Aplant breeder can then select which germplasm to advance to the nextgeneration. This germplasm can then be grown under differentgeographical, climatic, and soil conditions, and further selection canbe made during, and at the end of, the growing season.

Pedigree breeding is generally used for the improvement ofself-pollinating crops or inbred lines of cross-pollinating crops. Twoparents that possess favorable, complementary traits are crossed toproduce an F1. An F2 population is produced by selfing one or severalF1's or by intercrossing two F1's (sib mating). Selection of the bestindividuals is usually begun in the F2 population. Then, beginning inthe F3, the best individuals in the best families are selected.Replicated testing of families, or hybrid combinations involvingindividuals of these families, often follows in the F4 generation toimprove the effectiveness of selection for traits with low heritability.At an advanced stage of inbreeding (i.e., F6 and F7), the best lines ormixtures of phenotypically similar lines are tested for potentialrelease as new varieties.

Molecular markers can also be used during the breeding process for theselection of qualitative traits. Exemplary techniques for identifyingmolecular markers include, Isozyme Electrophoresis, Restriction FragmentLength Polymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs(RAPDs), Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNAAmplification Fingerprinting (DAF), Sequence Characterized AmplifiedRegions (SCARS), Amplified Fragment Length Polymorphisms (AFLPs), SimpleSequence Repeats (SSRs) and Single Nucleotide Polymorphisms (SNPs), toname a few. Markers closely linked to alleles or markers containingsequences within the actual alleles of interest can be used to selectplants that contain the alleles of interest during a backcrossingbreeding program. The markers can also be used to select toward thegenome of the recurrent parent and against the markers of the donorparent.

Mutation breeding can also be used to introduce new traits (e.g., one ormore root growth characteristics of the present disclosure) intoexisting varieties. Mutations that occur spontaneously or areartificially induced can be useful sources of variety for a plantbreeder. The goal of artificial mutagenesis is to increase the rate ofmutation. Mutation rates can be increased by many different meansincluding temperature, long-term seed storage, tissue cultureconditions, radiation (such as X-rays, Gamma rays, neutrons, Betaradiation, or ultraviolet radiation), chemical mutagens (such as baseanalogs like 5-bromo-uracil), antibiotics, alkylating agents (such assulfur mustards, nitrogen mustards, epoxides, ethyleneamines, sulfates,sulfonates, sulfones, or lactones), azide, hydroxylamine, nitrous acid,or acridines. Once a desired trait is observed through mutagenesis thetrait can then be incorporated into existing germplasm by traditionalbreeding techniques.

In some examples, a plant 140 of the present disclosure is a row crop.In some examples, a plant 140 of the present disclosure is maize,soybean, rice, wheat, sorghum, tomato, or alfalfa. Other row cropsinclude, without limitation, cotton, beets, grain hay, legumes (e.g.,beans, peanuts, peas, etc.), flowers such as sunflowers, other grains(e.g., rye or oats), sugarcane, tobacco, kenaf, and the like.

Certain aspects of the present disclosure relate to techniques fordetermining an effect of a plant-microbe interaction on a root growthcharacteristic. It will be appreciated that such techniques are realizedusing the devices and techniques of the present disclosure in a varietyof applications. In some examples, the techniques include positioning aplurality of sensors (e.g., conductor plate 126 or parallel conductorplate 626) around a soil location, planting a seed 540 in the soillocation, inoculating the soil location with a microbe or community ofmicrobes (or applying the microbe or community of microbes to the seedin the form of a seed treatment), after the seed 540 has grown into aplant 140 having a plant root 142, and after a plant-microbe interactionis established between the plant 140 and the microbe or community ofmicrobes, receiving data representing a root presence, determining aroot growth characteristic of the plant root based on the data,determining a reference root growth characteristic of a reference plantroot from a reference plant of the same species as the first plant, anddetermining the effect of the plant-microbe interaction on the rootgrowth characteristic by comparing the root growth characteristic to thereference root growth characteristic.

As used herein, a reference, when applied to a plant 140, plant root142, and/or root growth characteristic, can refer to a plant 140, plantroot 142, and/or root growth characteristic of a plant grown under adifferent condition as a plant of interest (e.g., a test plant). In someexamples, the reference plant 140 is in a soil location not inoculatedwith the microbe or community of microbes. In some examples, thereference plant 14 is in a soil location not inoculated with anymicrobe. In some examples, the reference plant 140 is in a soil locationinoculated with a different microbe or different community of microbes.

In some examples, the effect of a plant-microbe interaction on a rootgrowth characteristic is determined by inoculating a soil location witha microbe of interest and studying its effect on root growth (e.g., asdescribed above), thereby examining the effect of a particular, knownmicrobe on root growth.

In other examples, the effect of a plant-microbe interaction on a rootgrowth characteristic is determined by screening a variety of plants forparticular root growth characteristic(s), identifying a growthcharacteristic of interest, and then detecting a microbe resident on theplant or plant root, thereby screening for unknown microbes that affectplant root growth. In such instances, the techniques include positioninga plurality of sensors (e.g., conductor plate 126 or parallel conductorplate 626) around a soil location, planting a first seed in the soillocation, after the first seed has grown into a first plant having afirst plant root, and after a plant-microbe interaction is establishedbetween the first plant and a first microbe, receiving data representinga root presence from the sensors (e.g., conductor plate 126 or parallelconductor plate 626) of the plurality sensors, determining a first rootgrowth characteristic of the first plant root based on the data, andidentifying the first microbe. In some examples, the technique furtherincludes determining the effect of the first microbe on plant rootgrowth characteristics. A variety of techniques can be used to identifya microbe of the present disclosure, including without limitationdetection of nucleic acids by PCR, direct sequencing (e.g., DNA- orRNA-seq), and the like; microscopic and/or histological examination ofthe microbe; and so forth.

The techniques described above may find use in studying a variety ofplant-microbe interactions. In some examples, the microbe is abacterium. In other examples, the microbe is a fungus. It should beappreciated that the methods for determining an effect of a plan-microbeinteraction on a root growth characteristic of the present disclosurecan find use for a variety of bacterial or fungal microbes, as well ascombinations thereof. In some examples, the plant-microbe interactionare beneficial to the plant (e.g., as with rhizobia or mycorrhizalfungi). In some examples, the plant-microbe interaction are detrimentalto the plant (e.g., as with a pathogenic microbe). Examples ofpathogenic plant microbes include those of the genera Xanthomonas,Erwinia, Burkholderia, Pseudomonas, Sclerophthera, Fusarium, Pythium,Achlya, Alternaria, Rhizoctonia, Sarocladium, Thanatephorus, Sclerotium,Sclerotinia, Curvularia, Microdochium, Cochliobolus, Cercospora,Curtobacterium, Ralstonia, Peronospora, Pyricularia, Clavibacter,Agrobacterium, Xylella, Uromyces, Stemphylium, Verticillium, Coprinus,Aphanomyces, Phytophthora, Septoria, Passalora, Colletotrichum,Exserhilum, Macrophomina, Bipolaris, Claviceps, Ramulispora,Gloeocercospora, Phialophora, Diaporthe, Phoma, Puccinia, Tilletia,Ustilago, Urocystis, Erysiphe, Mycosphaerella, Leptosphaeria,Pyrenophora, Calonectria, Gaeumannomyces, Pseudocercosporella, and soforth. In some examples, the plant 140 is a row crop. In some examples,the plant 140 is maize, soybean, rice, wheat, sorghum, tomato, oralfalfa. Other row crops include, without limitation, cotton, beets,grain hay, legumes (e.g., beans, peanuts, peas, etc.), flowers such assunflowers, other grains (e.g., rye or oats), sugarcane, tobacco, kenaf,and the like.

In some examples, a plant-microbe interaction is established after aknown or hypothesized interaction during contact between a plant 140 orseed 540 of the present disclosure and a microbe of the presentdisclosure. In some examples, a plant-microbe interaction is establishedafter a particular phenotype of the plant or plant root 142 is observed,such as a visible effect on the plant itself (e.g., change incoloration, above-ground growth, appearance of blight, wilt, or othertrait, increased growth in the case of beneficial plant-microbeinteractions, and so forth).

As described above, the techniques of a non-invasive root phenotypingdevices 100, 600, 1100 of the present disclosure can find use intechniques for monitoring a soil organism. In some examples, thetechniques include positioning a plurality of sensors (e.g., conductorplate 126 or parallel conductor plate 626) around a soil location,planting a seed 540 in the soil location, receiving data representing aroot presence in contact with or proximity to a conductor plate 126 ofthe plurality (after the seed has grown into a plant 140 having a plantroot 142, and after the soil organism has invaded the soil location),based on the data, determining whether the detected root presence isfrom the plant root 142 or the soil organism, and in accordance with adetermination that the detected root presence is from the soil organism:monitoring the soil organism based on the data. In other examples, thetechniques include positioning a plurality of sensors (e.g., conductorplate 126 or parallel conductor plate 626) around a soil location (aplant having a plant root is planted in the soil location, and the soilorganism has invaded the soil location), receiving data representing aroot presence in contact with or in proximity to a conductor plate 126of the plurality, based on the data, determining whether the detectedroot presence is from the plant root or the soil organism, and inaccordance with a determination that the detected root presence is fromthe soil organism: monitoring the soil organism based on the data. Insome examples, a type of soil organism is monitored (e.g., the type ofsoil organism is inferred from its size). In some examples, the soilorganism's size is inferred based on, at least in part on, the durationof the signal response 1234 and/or the magnitude of the signal response.In some examples, a number of soil organism(s) of interest are monitored(e.g., based on one or more of duration of the signal response 1234, asignal response 1234 magnitude, and a number of detected roots 142). Forexample, a number of a particular organism (e.g., corn root worm) in aspecific location can be used to decide when to treat with a pesticide,the amount of pesticide to be used, and so forth.

The transient processes such as soil organism contacts can bedistinguished from root traits based on a number of aspects. Forexample, in some instances, the data includes information identifyingthe magnitude of the signal response. In some examples, thedetermination that a detected root is from the soil organism is based,at least in part, on the signal response magnitude. In some examples,the data include information identifying duration of a detected root atone or more the sensors (e.g., conductor plate 126 or parallel conductorplate 626). In some examples, the determination that a detected root isfrom the soil organism is based, at least in part, on the duration ofthe detected root In some instances, the determination that the detectedroot is from the soil organism is based on the magnitude of the signalresponse and the duration of the detected root. It should be appreciatedthat combination of aspects of the data, such as magnitude and duration,can be used to determine whether the detected root is from a plant root142 or a soil organism.

In some examples, in accordance with a determination that the detectedroot is not from the soil organism, the data is stored and/or filtered.For example, in some instance, a further determination is made as towhether the data represent noise/baseline signal or whether the datarepresent the presence of a plant root 142. In some examples, inaccordance with a determination that the data represent noise/baselinesignal, the data is filtered. In some examples, in accordance with adetermination that the data represent a true presence of a plant root,the data is stored in computer readable medium/memory 408 and/orconditioned (e.g., signal processor 412. This provides tracking of bothplant roots 142 and transient inputs from soil organisms.

In some examples, the soil organism is a worm or insect. In someexamples, the soil organism is an agricultural pest. In some examples,the soil organism is a corn root worm (e.g., Diabrotica virgifera). Insome examples, the plant 142 is a row crop. In some examples, the plant140 is maize, soybean, rice, wheat, sorghum, tomato, or alfalfa. Otherrow crops include, without limitation, cotton, beets, grain hay, legumes(e.g., beans, peanuts, peas, etc.), flowers such as sunflowers, othergrains (e.g., rye or oats), sugarcane, tobacco, kenaf, and the like.

It is understood that the specific order or hierarchy of blocks in theprocesses/flowcharts disclosed is an illustration of exemplaryapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flowcharts may berearranged. Further, some blocks may be combined or omitted. Theaccompanying method claims present elements of the various blocks in asample order, and are not meant to be limited to the specific order orhierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, hut they are to be accorded the full scopeconsistent with the language claims, wherein reference to an element inthe singular is not intended to mean “one and only one” unlessspecifically so stated, but rather “one or more.” Unless specificallystated otherwise, the term “some” refers to one or more. Combinationssuch as “at least one of A, B, or C,” “one or more of A, B, or C,” “atleast one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C,or any combination thereof” include any combination of A, B, and/or C,and may include multiples of A, multiples of B, or multiples of C.Specifically, combinations such as “at least one of A, B, or C,” “one ormore of A, B, or C,” “at least one of A, B, and C,” “one or more of A,B, and C,” and “A, B, C, or any combination thereof” may be A only, Bonly, C only, A and B, A and C, B and C, or A and B and C, where anysuch combinations may contain one or more member or members of A, B, orC. All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. The word “exemplary” isused herein to mean “serving as an example, instance, or illustration.”Any example described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other examples. The words“module,” “mechanism,” “element,” “device,” and the like may not be asubstitute for the word “means.” As such, no claim element is to beconstrued under 35 U.S.0 § 112(f) unless the element is expresslyrecited using the phrase “means for.”

1-15 (canceled)
 16. An electronic device for monitoring growth of a rootof a plant in a soil location, comprising: a support structure suitablefor arrangement adjacent to the soil location; and a plurality ofelectronic sensors affixed to the support structure, wherein at leastone electronic sensor of the plurality of electronic sensors comprises:a first conductor plate configured to be disposed in soil; a switchelectrically coupled to the first conductor plate, wherein the switch isconfigured to switch between a first mode and a second mode; a powersupply electrically coupled to the switch, wherein the power supply isconfigured to provide a first electrical charge to the first conductorplate in the first mode of the switch; and a signal extractorelectrically coupled to the switch, wherein, in the second mode of theswitch, the signal extractor is configured to extract a signal at thefirst conductor plate based on the first electrical charge provided tothe first conductor plate in the first mode of the switch.
 17. Theelectronic device of claim 16, further comprising: a microcontrollerelectrically coupled to the signal extractor, wherein themicrocontroller is configured to receive the signal from the signalextractor; and a memory electrically coupled to the microcontroller,wherein the memory is configured to store data associated with thesignal extractor.
 18. The electronic device of claim 17, wherein thesignal is stored in the memory at predetermined intervals.
 19. Theelectronic device of claim 17, wherein the switch is a multiplexer thatis electrically coupled to and controlled by the microcontroller. 20.The electronic device of claim 17, wherein the microcontroller isconfigured to: retrieve a baseline signal from memory; and compare thesignal to the baseline signal to determine whether a difference betweena portion of the signal and a portion of the baseline signal exceeded athreshold value.
 21. The electronic device of claim 17, furthercomprising: a second conductor plate configured to be disposed in soiladjacent to and substantially parallel to the first conductor plate,wherein the second conductor plate is electrically coupled to ground.22. The electronic device of claim 21, wherein a root presence isassociated with a determination that the signal exceeded a thresholdvalue.
 23. The electronic device of claim 21, wherein the baselinesignal response is representative of a signal of the electronic sensorin soil without a root disposed between the first conductor plate andthe second conductor plate or without a root that is in contact witheither the first conductor plate or the second conductor plate.
 24. Theelectronic device of claim 21, wherein a gap between the first conductorplate and the second conductor plate has a cross sectional area of lessthan or equal to about 1 cm².
 25. The electronic device of claim 21,wherein a distance between the first conductor plate and the secondconductor plate is equal to or greater than about 1 mm.
 26. Theelectronic device of claim 21, further comprising a polarity switchconfigured to exchange electrical coupling between the first conductorplate and the second conductor plate.
 27. The electronic device of claim17, further comprising a soil humidity sensor or a temperature sensorelectrically coupled to the microcontroller.
 28. The electronic deviceof claim 16, wherein the signal extractor is a voltage divider or ananalog to digital converter.
 29. The electronic device of claim 16,wherein the support structure comprises a stake or an auger. 30-34.(canceled)
 35. A method for monitoring growth of a plant root of anelectronic device comprising one or more processors, memory, and aplurality of sensors positioned adjacent to the plant root, the methodcomprising: electrically charging, at a sensor among the plurality ofsensors, a first conductor plate from a power supply over a firstpredetermined time, wherein the first conductor plate is configured tobe disposed in soil; electrically uncoupling the first conductor platefrom the power supply; extracting a signal at the first conductor plateover a second predetermined time based on the electrical charge providedto the first conductor plate; determining whether a portion of thesignal exceeds a threshold value, wherein a root presence is associatedwith a determination that the portion of the signal exceeded thethreshold value; and storing a root presence indicator to the memory inaccordance with the portion of the signal exceeding the threshold value.36. The method of claim 35, further comprising: electrically grounding asecond conductor plate, wherein the second conductor plate is configuredto be disposed in soil and adjacent to and substantially parallel to thefirst conductor plate.
 37. The method of claim 35, further comprising:determining one or more of: (a) root growth rate, wherein the rootgrowth rate is proportional to a three-dimensional coordinate of thesensor over an elapsed time; (b) biomass of the plant root, wherein thebiomass is proportional to a capacitance magnitude of the signalresponse; (c) biomass growth rate, wherein the biomass growth rate isproportional to the change in biomass over an elapsed time; and (d) rootangle of the plant root, wherein the root angle is based on an anglebetween a point of origin of the plant root and a three-dimensionalcoordinate of the sensor. 38-42. (canceled)
 43. A non-transitory,computer-readable storage medium comprising one or more programs forexecution by one or more processors of an electronic device, the one ormore programs including instructions which, when executed by the one ormore processors, cause the device to: electrically charge, at a sensoramong a plurality of sensors, a first conductor plate from a powersupply over a first predetermined time, wherein the first conductorplate is configured to be disposed in soil; electrically uncouple thefirst conductor plate from the power supply; extract a signal at thefirst conductor plate over a second predetermined time based on theelectrical charge provided to the first conductor plate; determinewhether a portion of the signal exceeds a threshold value, wherein aroot presence is associated with a determination that the portion of thesignal exceeded the threshold value; and store a root presence indicatorto a memory in accordance with the portion of the signal exceeding thethreshold value.
 44. The non-transitory, computer-readable storagemedium of claim 43, wherein the instructions which, when executed by theone or more processors, further causes the device to: electricallyground a second conductor plate, wherein the second conductor plate isconfigured to be disposed in soil and adjacent to and substantiallyparallel to the first conductor plate.
 45. The non-transitory,computer-readable storage medium of claim 43, wherein the instructionswhich, when executed by the one or more processors, further cause thedevice to: determine one or more of: (a) a root growth rate, wherein theroot growth rate is proportional to a three-dimensional coordinate ofthe sensor over an elapsed time; (b) biomass of the plant root, whereinthe biomass is proportional to a capacitance magnitude of the signalresponse; (c) biomass growth rate, wherein the biomass growth rate isproportional to the change in biomass over an elapsed time; and (d) rootangle of the plant root, wherein the root angle is based on an anglebetween a point of origin of the plant root and a three-dimensionalcoordinate of the sensor. 46-147. (canceled)